Indoor cycling normally isn't as fun as the outdoor variety, and it certainly isn't as social. Where's the thrill of blowing past a rival? That's what Zwift's upcoming massively multiplayer cycling game promises to solve. So long as you have a training bike with at least speed and cadence sensors, you can race people around the world in virtual environments -- think of it as an online role-playing game that builds up your real abilities. You can chat up other riders if you have a mic, and virtual reality support (through Oculus Rift headsets) might help you forget that you're still at home.