Do you have a time of year picked out for this evening?
These kids are too young to sit for a movie or to really do a game night, so if anything a simple craft night would probably be best.
If you were going to do it in the fall they could paint pumpkins and make easy halloween crafts.
Also we have a nursery school here that has a family dance and it is very successful! All the kids and the parents dance and the kids all really love it.
