There used to be a go kart place on Riverside in Portland, but I have no idea if it is still there or not. What about Lazer Tag? They do that at Jokers in Portland. Or even just a movie? The theatre in Bridgton has a little cafe, and a friend of my daughter did a birthday there once and they gave her a room for cake/ice cream too. Or rollerskating? My kids love that too and they have the option of renting skates or rollerblades at the happy wheels in portland.