S.H.
lots of great ideas already posted! Here's mine: we play Pin the Hat on the Witch....all made from poster board.
We also play Build the Skeleton. Freeform draw bones onto poster board, cut them out, & then let the kids pull from the pile. The whole group then decides where to place the bone.....great learning activity!
Find the Eyeball- draw an eyeball on a ping pong ball & hide it in the ball pit. OR hide it in the room. (I've also done this with a whole bag of ping pong balls so the kids have a fairer chance.)
Wrap the Mummy....using teams of two, a baby doll, & TP. It's a blast...a blast, but a mess. Be prepared for the kids' frustration too. Sounds like a downer with all of the precautions, but it truly is fun.
Catch the Ghost: hang mini white powdered donuts from a line, just at head height for the kids. Line the kids up & let them catch the "ghosts" with just their mouths. **Note: we do this even with the older kids, but use blindfolds. When the kids got my husband to do it, they cheated & moved the line up & down so there was NO way for him to catch the ghost. It was a RIOT & the kids were belly-laughing over it forever!
OK, that's all off the top of my head! If you want more ideas, feel free to contact me. Have fun....& by the way, this question was perfect timing because we have an annual Halloween party & my 13 y.o. has been busy planning it!