TweetTweetJam 4 is going to start very soon!!! 
I’m going to take part. I took part in the past and I can tell that making a game in just 560 characters of code is extremely fun (and frustrating at the same time, but that’s part of the fun).
I can guarantee you will learn a lot on how to write powerful and terrible code that nobody understands 
. Even yourself won’t understand anything you wrote just a few days afterwards… unless you cheat and place comments everywhere, which Imho is against the spirit of the jam 
Cheers!