I know of a fabulous place -- it's called "your house".
Seriously...what's with all the formal birthday celebrations for little kids? He's TWO for crying out loud. Kids that age have the attention span of a gnat and won't remember a darn thing about the day. Invite your family and a few friends over to your house so the grown ups can hang out and talk and your kid can nap/play a bit.
If you truly need to go out somewhere else, I suggest Bennigans because it has a huge playroom and an outdoor play area. But there are loads of bigger kids that go there too, so you'll need to supervise things quite closely with two year olds.