A "Make your own sound effect" game.
One poster names some action like say "Nightcrawler's teleportation". The next poster should write a sound he thinks would go well with it. Everybody knows NC goes "bamf" so come up with your own effects, use your imagination people. Then the poster who wrote the sound effect writes some other action so the next poster could write a sound to it etc etc I'll start.
Thor's Godblast.