Glad you are having fun! My kids often just love
being at a hotel and swimming too. You could go to Lexington/Concord. The boys probably wouldn't be all that into it, but you can walk along the battlefield and be outside at least. Also, not sure how close you are to NH, but there's a great Children's Museum in Derry.
http://www.childrensmet.org/index.htm Ben and Mei really like it there, it's small so it's very managable and right off of the highway.
The Boston Children's Museum is really cool. If you can take Neil with you sometime, you should definately go!
Have fun
Susan, mom to Ben (6) and Emelia (3)
When will our consciences grow so tender that we will act to prevent human misery rather than avenge it? Eleanor Roosevelt