A.C.
I work at the Bloomingdale Park District so maybe I'm biased, but we have an awesome Halloween event.
http://www.bloomingdaleparks.org/m-special_3.htm
I worked it last year and we had a blast! It will be a little different this year because the big gym is being redone after the recent flood, but it should still be great. My nephew was about that age last year, and he loved it too.