My kids love having tea parties. A little caffiene free hetbal tea, some homemade banana bread (or whatever)...they love it!
Find a large box and let them go to town on it. Endless hours of play. Keep an eye out for neighbors getting new appliances, or ask an appliance store for extras.
Make a tent with sheets, blankets, and the dining room table.
Picnic in the living room and a movie.