[vunderba]

> "publicly tweeted that I would send 30€ to a friend of mine if I didn’t have a blog post online by the end of the month."

Publicly tweeted huh? Well geez you're really on the hook now. Call me back when you've finished the app that forces you to place the money in a secure escrow which checks your blog's RSS feed to determine whether or not to return the cash.

On a more "serious" note, there have been quite a few of apps/concepts around a monetary penalty for not doing something - I think going to the gym was a big one. Probably be pretty easy to implement an app where you have to meet a GPS radial condition for X minutes per week.