College Startup Success Story, RevisitedGarrett Camp sold StumbleUpon for a reported $75 million a year after graduation. Then he bought it back.

In 2007, Garrett Camp pulled off an entrepreneurial accomplishment of a lifetime: He sold his college startup--StumbleUpon, a discovery engine that finds the best content on the web for each unique user--to eBay for reportedly $75 million, a mere year after graduation.

But Camp's entrepreneurial spirit shone even brighter in April 2009 when, unsatisfied with the results of the sale, he bought the company back. Since then, he has restored the energy of a college startup to what had become a corporate entity, tripled StumbleUpon's revenue and grown its user base 118 percent, to 10 million.