Mark Gainey and Michael Horvath were two friends from college with a good idea and bad timing: in 1995, they set out to create a digital community where athletes could chart their progress and actively compete with one another. But it was just too early: software engineers said it couldn’t be built, and investors didn’t want to take the risk. So the two founders wound up launching an entirely unrelated business, one that was so perfectly timed that it led to a successful IPO a few years later. Still, Michael and Mark couldn’t shake their original idea, and in 2008, they launched a website where cyclists could map and monitor their rides, and compete with riders across the country. The prototype was clunky—Mark jokes that “we wanted to make it as hard to use as possible”—but the timing was perfect, and Strava was born. Today, it’s a mobile app used by 100 million athletes in nearly 200 countries around the world.