My Son`s B-Day

My son will be 9 on Aug 2. It is far away but I want to have a party during the schol yr. I don`t want to do the typical party at a place where you pay tons of $ for an hr or hr + a half. I may want to do a party closer to the Summer because we put a pool in last year. I just do not want it to be swimming + cake. I want something special. He is to old for a character to come. I want to make it special + Fun. Help!!!