I saw something like this on pkto's boards.
GOAL: APK, as a community, does 10,000 pullups. If you can't do pullups, do chin-ups. Or kipping pullups. Or jumping pull/chinups.
Once you've done some, post here with how many you did, and then the new total.
Example:
Pull ups: 20.
New Total: 5,400.
Go for it! Let's see how quickly we can work together as a community to do a ridiculous number of pullups. (If this takes off, when we've completed this task we can do a different exercise.)