ok. a good sleepover game is called bear. its basically like hide and seek in the dark (so play at night). First, divide into two teams. One team goes hide outside (most people have at least a couple good hiding places). Then the other team comes to look for them. When they get close the first team jumps out and screams. It usually scares the crap out of you and its really fun.
ANother game is sardines, which is basically like it, except only one person hides. The rest goes and looks for her. Just make sure the other kids dont stay together. It ruins the fun. Anyway when you find the person hiding, you hide with her (or around in that area). The last person left looking is the next one that hides.
Also you can play killer in the dark. Another outside game (i hope your parents dont make ya'll stay inside). Any way to play this game you get enough strips of paper for all the kids. On all but 1 you write townsperson. On one you write killer. Everyone runs off and hides (including the killer). Then the killer finds them and taps them on the shoulder. The person waits 10-20 seconds, and screams. Then everyone else gets to guess who the killer is. (includng the killer to throw people off)
Hope these games help. If you have do stay inside, you can always rent some cool movies and just chill.