I like the idea of a community map based on themes. It could start off easy with something like bike trails, but starts being more interesting when you map Christmas light displaysss, sitting benches, fruit trees, scenic photos, etc. There are two keys to making this sort of thing happen. First, you need a good, flexible map that can display different layers of information...down to the street leve. Second, you need a way to make it interactive allowing people to submit, search, etc. The new popularity of GPS systems makes this even more interesting.