What should I do for my 2 year old boy's b-day party?

They sell little bounce houses that you can put up inside. They run from about $50 to $250 check the Toys R Us web site. They are always fun and you can use it when you have your play dates. When my son has his friend over we do play dough sometimes but that is only with two kids! We always have the no one leaves the table while the play dough is out rule in full affect when we do it. You could make up some games for them to play. Get some buckets and some and have ball and bucket toss, you can do limbo, musical chairs, you could do crafts and make musical instruments and then let them play them. Just try and get a couple of organized activities to do so they can focus on doing that.