We are suffering from insanity-inducing cabin fever around here. I'm going to be referring back to this list all day to keep my 3 year old busy: 10 Indoor Activities using Household Items by On the Banks of Squaw Creek
I use these photo blocks in our block center. I take a full body shot and cut it out and then just tape it to a block. the kids love using them both in the block center and for other games they invent.