Hi there,
there is a web site somewhere with lots of ideas for party games for different ages. We played one at my daughters 11th party which went down really well. Put loads of silly clothes like bra, hats etc in a bag and play pass the parcel with it, whoever it lands on has to put it on, you can also add in dares if they choose instead (just to save too much embaracement) dares like sing ba ba black sheep or hop on one leg, you get the picture? It worked so well and the boys loved it (very into the dressing up, making the girls laugh), the photos were brilliant too.
There were others too but that was definately the most sucessfull. I think the winner was the one judged best dressed! when the clothes had gone.
Hope you have a lovely party.