Social exercise platform, Fitocracy released for Android
The idea is pretty simple: combine exercise with motivation from your social network, and gamification in the form of quests, experience points, levels, and badges. So, not only can you track your exercises, but keeping on your routine, and getting fitter will earn you achievements. You get points for working out, and there are optional quests each day to earn you even more points. Not a bad deal.
Of course, as with any social platform, you'll get the most value from it if you can convince other friends to join the service, but that should be easier now that the app is available for both iOS and Android.