yeah thats just a girl thing, with boys its completely different unless its flirting. Just make sure you have lots of munchies (crisps, ice cream, pizza, pepsi etc), maybe a few cans of lager - only enough for about 2 each, a few movies would go down well coz no doubt they wont go to sleep until at least 3am. I cant really help with the music thing, maybe raid a CD collection? Other than that, keep adults away (obviously check on them or watch from a distance). It will be fine but you will probably need a weekend to recover from it all!!! Good luck!