Last time, we did a 20 brush compo. This time, it's THE CUBE; make a single player or multiplayer level, any game / mod / engine, as long as it's within a 1024 x 1024 x 1024 cube (or whatever engine equivalent.) That's it.
You have about a month. Get cracking!
Oh, and for reference, here's Duncan Blair's winning entry from the last cube compo we did. Ooooh shiny: