Rainy day: Bring from your home library: The Big Book of Games; How to Nothing, All alone by Yourself; bring a few decks of cards and learn games, tricks and how to build a house of cards. Play a game: Let's see who can be the quietist while I take a nap. The current compulsion to schedule adult organized activities is, IMHO, a negative for building imagination and self sufficiency. We were told "Go outside and play, come home when the street lights come on. (We don't have street lights in my area, but otherwise a good NH activity.) In a motel or cottage colony? Go knock on doors and ask for kids. There will be other families not knowing what to do and everybody will be happy to make new friends. Put sticks in the ground and see who can knock them over with a Frisbee. The folks at the local tackle shop would love to sell some cheap tackle and teach some basic skills. (You need a license, the kids probably don't.) If you are absolutely compelled to spend money, rent a boat, get rides at the local airport, go horseback riding. Ride the Mount rain or shine. Instead of climbing Mount Major (free) go to Gunstock and take the chairlift to the top, or get a similar view by hiking to the fire watch tower from Gilford Village. Lots of Old Home Days in August, parades and free stuff. Really stuck?
www.visitNH.gov. I could keep going, but you get the idea...