Spevak is the CEO of Equinox, the increasingly omnipresent chain of high-tech-looking gyms that Danny Errico founded in 1991.

An accountant by training, Spevak started his career toiling in the audit department of Touche Ross (now Deloitte Touche). In 1988, at all of 24, he started a sporting goods retail chain, Manhattan Sports. Six years later, he spotted Chelsea Piers chairman Roland Betts while jogging and took the opportunity to pitch him on the idea of a health club for the pier. Betts didn't bite. But after a barrage of follow-up phone calls, he finally went along with Spevak's proposal and hired him to launch the Sports Center at Chelsea Piers, which quickly impressed New Yorkers when it opened thanks to its unusual amenities, including rock climbing walls and an indoor beach volleyball court. Spevak left in 1999 to take the reins at Equinox Fitness Clubs, known for its luxurious gym facilities housed in upscale buildings. The chain has since expanded across the globe, but most of the gyms are concentrated in major metropolitan areas like New York, Chicago, Los Angeles, Toronto, and London. [Image via Getty]