Storyland in Glenn, New Hampshire. It is the nicest, cleanest amusement park ever! It's also pretty old - many people I know say that they used to go there as a kid (25 years ago) and that it hasn't changed! It IS geared to children probably 10 and under (my 9 year old never wants to stop going, though, and we always see kids older than her).

Since it's in the mountains, there are great things to do other days: gandala (sp) rides, hikes, and climbing (or driving) Mount Washington - famed for having the worst weather in the world on top! Amazing restaurants and shopping in North Conway and outlets nearby. The most family-friendly area I've been. We go back every year!