No-effort entertainment: Glow sticks
To all you parents who haven't tried these yet (or lately). Glow sticks are fun!! I know it seems like a big "duh," but every time we get them out, my husband and I wonder why we don't do it more often.
I pick them up at the dollar store and stash them in the cupboard, and then on a night when he and I are both too exhausted to do much else, we sit on the floor in the dark and let the kids entertain us. It makes for a great family moment. Even the seven-month old is entertained, and the only work we have to do involves telling the three year old and five year old to stop fighting over the pink one.
More: Halloween hacks