RE: Halloween party ideas for 2-3 year olds?
I second the toilet paper idea! It would make for great photos!
I might also try hanging donuts from string at various lenghts across the room for them to try to eat off without touching it with their hands (this was a big hit at a party we went to, but the kids were a little older)
Pumpkin bolwing - I found 6 plastic pumpkins (similar to the size of the pumpkin buckets you can find everywhere right now that kids use as Trick or treating buckets) and I stacked them in a pyramid and gave them a small pumpkin gourd to roll into the plastic pumpkins.
You could also set out some Halloween themed pages to color (I googled and found a ton to print out). or stickers - can't go wrong with stickers!
I would also just do a few fun and crazy treats - mud cups (chocolat pudding with crushed oreos and gummy worms), cheese cut in shapes of ghosts, some crazy punch - again, Google is a wonderful thing for this!
DD#1 is 7 years old
DD#2 is 6 year old