(FORTUNE Magazine) – And you think your taxes are tough? The IRS doesn't mind if you collect clocks--or do anything else it considers unusual. It just wants you to fill out a few little forms.

Greg Raymer surreptitiously jots down a few figures in his spiral notebook: "Foxwoods 4/17, no limit Hold 'em tournament, $220 in at 12:02, $0 out at 5:30, minus $220, 5.5 hours." It's just the first in a series of hasty entries he'll make in his notebook during the three-week tournament. By day a patent lawyer, Raymer spends around ten hours a week gambling, netting more than $10,000 in a good year by playing poker variations like Texas Hold 'em, seven-card stud, and Omaha high-low.

But because even amateur gamblers are supposed to pay taxes on their winnings (and can adjust for their losses), the IRS mandates that he keep precise records of every session he plays all year. If Raymer, 36, plays one hand and then switches tables--yep, he has to make a whole new entry. It's as tedious as, well, filling out tax forms--only Raymer has to do it hundreds of times a year. Come tax season he'll compile all his notebook entries for the year and tally up his wins and losses for the IRS.

Much to his chagrin, Raymer has become the unofficial in-house tax expert at the Foxwoods casino in Mashantucket, Conn., where he usually plays. Other gamblers buttonhole him in the men's room to ask about everything from itemization rules to whether they should file as professionals so that they can write off travel and entertainment expenses. While standing at the casino urinals, Raymer will hold forth on, say, the relative merits of using a Schedule C or Schedule A. "Sometimes I think this is some kind of nightmare that I understand this stuff," he says with a laugh. "Does this mean I was born to be a tax accountant?"

And if you think Raymer's got tax headaches, he's not alone. Just about anyone with an offbeat job, or even an offbeat hobby, often ends up with an additional part-time gig as a Dickensian clerk--keeping reams of dusty, hand-written ledgers filled with excruciatingly small numerical detail.

And hey, if that kind of torture isn't enough, there's always the specter of the ultimate "procedure," the one that makes a root canal seem pleasant by comparison: the federal audit.

Serious collectors, for instance, who do a lot of buying and selling, bear no small amount of IRS scrutiny. "I have clients who are wine collectors, coin collectors, art collectors, baseball collectors...you name it," says Ralph Anderson, a partner at Eisner tax consulting in New York City. "When you have rare collectibles like that, you have to keep meticulous records." The requirements, he says, "drive all my clients nuts."

One of Anderson's clients buys and sells clocks for fun, and has filled three rooms of his Massachusetts home with everything from grandfathers to cuckoos. With such collections, says Anderson, the owner has to keep records of the original cost of each item, documentation of travel or expenses involved in acquiring it, evidence of whether he hired someone to find it, and receipts for any cleaning, repair, or improvement.

A hassle? That's putting it mildly. Anderson's client has 350 clocks, worth a combined $4 million to $5 million. When Anderson told him, back in 1984, that he'd have to do all this record keeping, "he was blown away by it. You know, most people who collect items like this have some type of net worth, and when you tell them they have to spend all this time keeping track of receipts, they get very upset. They just can't believe it."

For Anderson's client it meant starting an office, which for the past 15 years has been progressively crammed with a current total of 350 plastic binders, each of which has a detailed history of a particular timepiece. Only when he sells one, and adjusts his gain or loss based on his expenses, can he retire the binder. He also has to keep exacting records of the relevant improvements to his house: according to Anderson, that includes central temperature control and humidifier systems for the clock rooms, as well as one room that the man had soundproofed. "That room was for the cuckoo clocks," Anderson says.

Anderson's client has never been audited. Should that occur, those meticulous records will be his best shot at emerging unscathed. Robert Doyle, a CPA from St. Petersburg, tells the story of two of his clients, both involved in direct marketing ("The IRS hates direct marketers," he says, "because they all lose money, then try to write off all their business expenses"). The first client, who had consistently lost money for eight years, was audited but had several journals done in extremely neat handwriting and itemized receipts for all purchases, and generally ran the operation "like a business." The audit took two hours, and the client didn't end up owing a cent. The second client, who was in a nearly identical situation, came to the audit with "a briefcase stuffed full of receipts" and was socked with a $200,000 tax bill. Says Vernon Jacobs, a CPA who practices in Prairie Village, Kan.: "When an IRS agent comes in to audit, they want to see indications that this person is a scrupulous record keeper. The more clues they get to the contrary, the more opportunity they have to make that person's life difficult."

That's why when Don Haase, a retired schoolteacher from Everett, Wash., hops into his car and turns on the engine, his first instinct isn't to check the gas gauge or listen to the carburetor or adjust the seat. Instead, with the car still in park, he reaches for the spiral notebook he keeps on the passenger seat and makes his first entry of the day: "11:05, to post office for customer mailing." When he returns, usually no more than 15 minutes later, he'll make a closing entry with the final mileage tally. Says Haase: "It's a lot of writing." But as Haase--who calls himself "Mr. Spode"--well knows, it's just a small part of what the IRS mandates for anyone who writes off business expenses.

As a 12-year veteran of the Spode china business ("only pre-1965," he says), Haase spends roughly an hour every few days reconciling his records for the IRS. There's an identical notebook in his pickup truck, and he'll tally those entries in a master mileage and gas notebook in the house. Then there's his ledger. (When open, the 16-column pages measure nearly 2 1/2 feet.) There he lists every pen, paper, eraser, paper clip, mailing expense, or other business supply that passes through his hands. And he has another binder where he records the details of every dinner plate or serving dish that he buys or sells (Haase typically has around 7,000 items in his possession and sells up to $60,000 of the stuff a year).

What's more, when he travels around the country looking for the perfect teacup or unchipped salad plate, those flights and meals can be written off--provided they are properly documented. That's why Haase has kept and filed the receipts for anything and everything having to do with his china collection for the past seven years (the garage is full of receipt boxes). "It's amazing how many records you have to keep--but you've got to keep on top of it," says Haase, who has been audited twice. "Because if you let it go for a couple weeks, it's just chaos."

And "chaos," in the lexicon of tax experts, means "hell to pay." Just ask Dr. Kendall Harmon, who still has T-Day (April 12, 1998) emblazoned in his memory. The Summerville, S.C., Episcopal minister had been putting off doing his taxes for weeks. But with April 15 closing in, there was no more delaying. Harmon had more cause than most to be apprehensive--1998 was the year he became what he calls an "active" stock trader. In fact, he had racked up some 7,000 trades that year. So clad in khakis and an old T-shirt, he flicked on his computer and spread out dozens of files on the immense green Formica desk in his home office. "I still remember: I was literally sweating," says Harmon, "and I was wondering if I could get it all done in time to write a sermon for the next day." Because his discount broker didn't have software that allowed him to download his trading records into Quicken, Harmon had to manually enter every trade into the spreadsheet for every day of the year--then cross-check them with his month-end statements--making sure to adjust positions for, say, the wash-sale rule (which restricts the ability to write off losses in a given stock if you buy the same stock within 30 days).

Though he had been relatively diligent about doing this throughout the year, there were tons of careless errors, such as incorrect prices for certain stocks or trades that were omitted. "My wife and I were both huddled there with calculators and pencils, checking things off, and she actually said to me, 'I don't know if you can continue to do this and stay sane.'" Though he did finish the project in time, it was "basically taxes or bust, and it just about ended up being bust." Which is why Harmon enlisted professional help when tax time next rolled around.

But even with outside counsel, the record keeping doesn't go away. Every time he makes a trade (remember, we're talking hundreds and hundreds of transactions a month), his brokerage sends him a page-long trade confirmation in the mail, which must be saved in case of an audit. "My wife puts them all in binders," says Harmon, "but these things are unbelievable! They're overflowing from the attic. We've got boxes on the bookshelves--they're clogging up the office." And the last expense he tallies up? Mailing costs for his tax returns--Harmon has the dubious honor of boasting a Schedule D that usually runs upwards of 20 single-spaced pages.

"There is a huge record-keeping burden for day traders," notes Robert A. Green, CPA of GreenTraderTax.com (and Harmon's new accountant). "People come to us, and they are tearing their hair out trying to keep up with all the paperwork and all the tax laws."

But perhaps the oddest tax paradox, as Al Capone could have told you, occurs with professional callings that are less than legal. Even if you're in the felony business, the IRS expects you to pay up. Take the case of Armin Unger. His alleged drug dealing was hardly his only faux pas in the eyes of the IRS. He also neglected to file his tax returns in a timely manner. According to a U.S. tax court ruling, Unger "argues he did not intend to evade taxes he knew to be owing. He claims that he wanted to, and intended to, eventually pay his taxes. He claims that he failed to file returns only because he believed that if he filed returns, it would expose his criminal activity to other law-enforcement agencies." Not a good enough excuse, apparently.

Unger, who could not be reached for comment, was in court again in August, where he quibbled with agents about how they determined how much tax he owed. Since the IRS agents can hardly reconstruct a history of cash drug sales, they use what's called the "net-worth method," in which they tally the suspect's cash, traceable bank accounts, and any other known assets. Unger declined representation, instead mounting his own defense (one of his more memorable arguments: He claimed a $10,000 check drawn on his account was originally made out for $10, then altered by the recipient). Unsurprisingly, he did not prevail. According to the tax court's findings, Unger "admitted to illegal narcotics trafficking, conducted his business almost exclusively in cash, used aliases..." and in addition, committed the cardinal sin in the eyes of the IRS: He "kept and produced no records of his transactions."