Okay, I know all of you hate games, you think they're childish and all that, but if you want something fun, fun, and fun, and you own a PS2, honestly, this is brilliant :
Global Defence Force. Basically you run/fly about destroying tons and tons and tons of B-movie-inspired aliens, flying saucers, spiders, ants, etc.
I picked up the Japanese version of this a few months back. It's easily the most fun I've had with a game in ages.
Oh well, had to mention it, for what it's worth.