Let's say someone decides to go contra dancing or to a LessWrong meetup. Right now this means either looking through long lists (contras, LW meetups) or sites that try to let you search (Dance Gypsy, DanceDB, QuakerFinder) but because they're written and maintained in the spare time of volunteers don't do it well.

What dances and meetups have in common is that they are loosely franchised [1] repeating events. It's silly to build complex sites like the Dance Gypsy for each community that's interested, and because that's so much work many communities that might benefit from one don't have it.

What if there were some sort of locator site? One person would use it to create a contra dance 'community' locatorwhatever.com/c/contras, someone else make locatorwhatever.com/c/lesswrong and maybe another would do locatorwhatever.com/c/quakers. The main page for each section would be a place for you to enter your zip code and see nearby gatherings. Either the admin for a community would be responsible for keeping it up to date or they could delegate to people from each local gathering (so maybe Don would maintain locatorwhatever.com/c/contras/ConcordMonday while Sally would do locatorwhatever.com/c/contras/BIDA but someone else would manage all of locatorwhatever.com/c/lesswrong). Each entry would be pretty minimal, with the organization's own website providing most of the detail. Maybe you'd just have name, location, schedule pattern, time, contact, and website. If you wanted to get fancy you could allow admins to add special fields that were relevant only to their kind of event (experience level, style, age range). Maybe include reminder email list management?

Please tell me that this already exists, is good, and I can start using it?

Update 2014-03-03: I made one of these just for contra: trycontra.com. You could easily adapt it to other communities, but I wasn't interested enough to do this.

[1] There's no umbrella organization for contra dances, but they're pretty similar all over the country.