(FORTUNE Magazine) – Judging from the guests at Procter & Gamble's alumni gathering, the business world is run by Proctoids. GE's Jeff Immelt, 3M's Jim McNerney, and eBay's Meg Whitman were among 350 former P&G employees at last month's reunion in Cincinnati. Though the alums have been convening for years, a P&G CEO has never attended--until A.G. Lafley. "This is an incredible resource," says the self-effacing chief.

P&G's reputation as the business world's best boot camp is legendary. Immelt recalls toiling to build Duncan Hines on "two or three hours of sleep." He shared a bullpen with the manic Steve Ballmer, who quit for a startup called Microsoft and ended up as CEO. McNerney began as a marketer on Downy, and Whitman helped launch Ivory shampoo. Steve Case, meanwhile, worked as a brand assistant on Abound, a towelette hair conditioner. He persuaded his bosses to install motion-activated monitors that played Abound ads in supermarket aisles. The ploy and the product bombed, losing $20 million. But there's life after P&G. "I knew this interactive thing would work someday," says the man who created AOL.