The Cafe Random thread is for questions or whatever. Drop in there. It's getting a bit long, so we'll be retiring it and starting a new one soon, but for now, that's the place to start if you want to introduce yourself.
I don't know if there are any collaborations going on this moment, but they pop up when the whim takes us. There's a folder for them in the forum. Feel free to start a new one if you don't like any of the ones that are there. We're in the process of retooling, as we've been going for a while and now we can see what works and what doesn't.
But yeah, short answer, drop on by and start posting!