Seriously this map is for adults only and is NSFW.
This Google Map mash-up geo-tags the messages in Craigslist's "Casual Encounters" section. Currently the site is only indexing New York, the San Francisco Bay Area, Los Angeles, San Diego, and Washington, DC.
To help find your ideal casual partner you can filter the search results by location and by sex and sexual orientation. You can even filter out those who post without photographs. The results are then marked on a Google Map with little red hearts. Clicking on a heart loads the results into the map sidebar. Clicking on a sidebar link opens the original message on Craiglist.