SuRpRiZe PaRtY HElP PLz??

Hey guys.. Me and court are throwing a surprize birthday party for our best friend laura this friday cause her mom wouldnt let her have a party. Shes turning 13, and the party is in courtneys basement. Were not exsactly sure how were gonna "surprizse" her, and were sooo not sure what were gonna do. If you could help us out with some ideas, it would be so great!!
Thanx!
~Court and Chelz