This one isn't exactly rocket science, but it looks like it could blossom into a useful service: Parentography. This is a user-generated directory of things to do with kids. It reminds me of Chowhound (now a CNET property), a restaurant reviews site written by foodies for foodies. This is pretty much the same thing but for parents (sadly, few venues are good bets for parents who are also foodies).
Parentography has reviews of museums, parks, restaurants, and other venues that its members recommend (or don't) for families with kids in tow. It also has a section for "excursions," which are recommended family outings. As implemented right now, there's no essential difference between a review and an excursion: There are zoos listed in excursions and resorts in reviews. I think it'd be cool if the site supported the creation of trip suggestions (with mapping support--see my write-up about Platial and two other related geo sites) that collected reviews into itineraries, like the "3 Perfect Days" feature in the United in-flight magazine. That'd make more sense and would be pretty useful. Update: See the first TalkBack comment. There is mapping in the excursion feature that's designed to do just I wished for. Unfortunately it didn't work quite right in my test just now (the link to Yahoo Maps for directions malfunctioned), but the concept is spot-on.
Parentography is basic, but it has the potential to become a nice community for families on the move.