What about making a cubby house under the table or something. last year for Erin's birthday we got her an indoor play cottage and it was the best thing we ever brought. ATM Kids Central (formerly Early Learning Center ) is having a huge sale and they have a rocket ship pop up cubby for only $50. Jill Bull has a Rainy Day activity book too.

I don't let the kids do this one often, but sometimes I will darken the loungeroom and give them a torch to run around with.