Original recipe and ALL THE THINGS seem to be winning. Perhaps all is the way to go. :3
I don't think doing all of them at once is a smart idea, but doing one then doing another, then maybe doing another is quite possibly the way to go.
1 piece original recipe and a robot chicken sounds good!
Those are the two I'd most likely contribute to, provided it's all in the summer when there will be more time. The only problem with doing a video though is that it is a lot more involved than some of the others, you need to make sure people finish their submissions and that they don't look terrible - if it all comes together it could be amazing.
Let's have a big old sing-along. Have members pick a line from "Girls just wanna have fun" make them record them singing the line, and mix it up in one great mess of a song.
I remember being part of one like that on the Gamespot ps3 forums some years back... We sang Snake Eater. Dunno if I still have the finished product lying around...