Orange balloons make simple pumpkin decorations with drawn on faces and green tissue paper stems from hwtm.
Good for ages 5 and up.
Get the instructions here:
http://blog.hwtm.com/2013/10/halloween-diy-balloon-pumpkin-patch-easy-fast/
Awise makes ghost balloons as well.
Site is no longer available.
Martha Stewart makes a carnival style game. She takes a bunch of orange balloons and arranges them to look like a pumpkin. She then fills them with candy and confetti and lets the kids pop them to get the prizes.
Get the instructions here:
http://www.marthastewart.com/269871/halloween-games-pop-goes-the-pumpkin