teen birthday party ideas?

Im having my 14th birthday party this febuary and its theme is sorta winter wonderland-y-ish… haha… im inviting around 6 people (boys and girls)…. i live on a lake that freezes in the winter so we r going to ice skate on it… but i cant think of any other ideas to do at my party… we will be ice skating for a while probably but i dont want to just skate my whole party because i want to top my birthday from last year:
we went on a SCAVENGER HUNT all around town. my mom drove one team in her car and my dad drove the other team in his car. we had clues leading us to different places and we had to find and buy different things. we had team t-shirts too.
so yeah i wanna top that. What are some not stupid activities we can do? we are all 13 and 14 except for my one freind who is 11. it doesnt matter if they are indoor or out door activities. thanks soooo much!!!