M.G.
Pin the mouth on the pumpkin: Cut out a large orange poster board pumpkin, glue black eyes and nose on that you have cut out from construction paper. Cut out a mouth from black construstion paper (do not glue on). The day of the party tape the pumpkin to the wall and just use scotch tape on the backside of the mouth for kids to try and put on in the right spot while blind folded. Be sure to bring extra tape, the tape will work for 2-3 kids before you need a new piece.
Pinata: to stay with the fall/halloween theme put spider rings, small halloween eraser, halloween stickers and candy in it.
I hope you have a great party!