How about silly putty......the kind where you can copy onto it......and what about those wall things you can throw against a wall and they stick.....never mind, 5 year old aim might not be good........!
For a side dish, make vanilla pudding and put in green food coloring!
How about a dress up game.....put clothes out for them to dress up in.....fake mustaches, etc.....maybe even something like the costumes they wore.....or put little things on it.....
Maybe some marshmallow guns.......
How about pin the whatever on the ghost? You know with it being around Halloween, get some sort of poster or something and pin something on the ghost......
You could also include a showing of the movie and maybe play the music during the party.......
I hope this helps.....great choice in a movie, even if a little old!! Take care and good luck.