Serious movies aren't worth watching as a group because you should get into them rather than make fun of them (hence why Mean Girls was ideal). Go for funny things. Tropic Thunder was good, btw, I liked it - particularly Tom's character.
Watch Superbad or a really bad film like Chicken Park. Actually, don't watch Chicken Park, it's got porn in it and that's probably not cool. I don't even know. I'll probably not be around so yeah.