Yeah I do have quite an interesting idea... but I don't know that I'll get it implemented, because it involves physics and I also don't know if I'll have the time. Although this "competition" does seem more flexible, offering you to pick a week out of a month.

I'm certainly not going to implement my own physics, and it looks like SDL doesn't ship with any (and I can't find any quick solutions). Andorra's got support for newton, but I have yet to be able to find a working lib for linux (because the version of Newton is interchangeable).