By Rhonda Johnson

(MONEY Magazine) – JUDI SHEPPARD MISSETT, 47 President, Jazzercise Inc. (est. 1977) 1990 revenues: $45 million

Judi Missett has an ex-boss to thank for turning her from wage slave into business owner. In 1977, she was working at a California health club to pay the rent and teaching a dance-workout class she called Jazzercise on the side. ''I wanted to quit and develop it into a business,'' she says, ''but couldn't because my husband was still establishing himself as a freelance writer.'' But she spent so much time on Jazzercise that her boss finally fired her. ''That made me take the plunge,'' says Missett, shown above in 1979. ''Now we have 4,500 franchises.'' -- R.J.