At my sons first birthday he has kids there old as well. We had a pinata. You could also rent one of those moonwalks for the older kids to play on. At the time we had a trampoline the kids jumped on. Craigs list sometimes has ads for moonwalks in different locations.
Some games I planned for my daughter's party: Bought several inexpensive socks threw them in a pile on the floor and then it was a race to see who could put on the most socks.
You could google party games. But mostly have some independant play area's for all ages to keep kids busy.