I dont know much about sleepovers. i just have them. usually with pizza games and a lotta random talking and laughing. If youn have a friend who is coming over i think the best thing for you to do is ONLY invite who you want to come. AND if there is anyone that you feel obligated to invite do your best to make it sound really bad and dont give her all the information straight. make it almost at the last minute. and say you "think" it will be at a certain time. If you say something is going to happen at the party the person wonbt like, she probably wont go. if you dont like eachother, then there is no sweat in lying and saying someone she ABSOLUTELY can not stand is coming over. Good Luck.