Sweet Sixteen coming up soon! Please help?

Okay so my birthday is coming up in less than a month and I still have no clue on what to do. I either have the choice of having just six of my closest friends for a sleepover or I can have a small party at my house with my group i hang out with. I really don't think it's necessary to wear a dress or anything formal since I'm around my friends and its just an informal party. I don't know what to do as in activities since we're all silly. Please don't suggest drugs, alcohol or . Honestly I'm not that kind of chick. Any suggestions would be nice except the ones I just listed lol. Should I have a theme? Maybe it will help you by what I like. I love watching Hawaii Five O and CSI. I like Tron, Transformers, and hawaiian beach looks(kinda). I also like the 80s and the colors purple, lime green and turqouise. Also please keep it inexpensive. Money is tight so maybe 150 dollars or less. around that.