Hey hansn, sorry about not getting back to you about this sooner. I believe in the past people have collaborated but the projects died, as they are apt to do if enough time passes and there aren't enough people on the project (a few people at a time get too busy, and come back to find the project isn't as active anymore and don't really revive it). Also, I know there are some people who have worked on (a) game(s) which is always a popular idea but people like me don't care as much for stuff like that.
If you're really very interested in collaborating on something, my best suggestion is to create a Bitbucket/Github project, populate it a bit, then post here with a pitch about why people who work with you on it. You probably won't get anyone, just because if they have the time they'll have already devoted it to something else, but you never know if someone new will come along, see it, and want to join in. You just have to have a lot of individual determination and not get let down when you do a lot of it yourself.
thankyouterror, pretty much the same advice to you, get something started, make a post, and cross your fingers. I don't think there's enough to this that a subforum is worth it, if anything, it might just make it easier to ignore (I ignore entirely the GUI and Games sections on this forum). Anyway, welcome to the forum!
Join the #python-forum IRC channel on irc.freenode.net!