I've never really been one for direct competition. I tend to prefer working with a team as opposed to fighting against other people, it's just how I operate I suppose. But even I have to admit Spin Island might be on to something here. Their new app, iBeatThat, is something akin to a social networking YouTube hybrid with a decidedly "Top that!" vibe. Competitive types (read: normal people) will no doubt eat this stuff up.
The overall premise is simple: users pick a "real world activity" such as snowboarding, basketball, etc... and take a video of themselves doing something impressive in that category. Once that's done, they can upload the clip through the app and see what happens. Which is to say, other users can view the video and rate it or even attempt to one-up the feat and see what the community thinks of their own attempt. They can also issue direct challenges to people on their friends list.
Would-be daredevils or "physical activity" enthusiasts will no doubt get plenty of use out of iBeatThat. And they can give it a spin right now for free. Just remember to play it safe, folks. Don't go getting seriously injured out there for the sake of fleeting notoriety.