Go to a park! It would be fun to have it outside where kids can just run around and the parents can sit and relax. The first birthday is more for the parents anyway. You get more stuff for the baby, a chance to hang out with other adults, you get to eat cake... all the good stuff. I would do it at a park so you don't pay per person, people can come and go as they please, and you really don't have to clean up too much.