if you're looking for mr. or miss "right now" craigslist offers good access to people in your geographical area. i won't speak to how satisfactory the results are, since i've never been quite horny enough to throw away caution and run off to let a perfect stranger fuck me on 60 minutes notice. You don't say if you're looking for straight or gay, but the chat rooms in gay dot com are good places to meet up with a gay man for some nsa. They also offer an opportunity to get some idea of what another person is all about, and to webcam or exchange jpegs. I've had a couple of decent hookups that way. You might also try the im boards on Alt, Outpersonals and Adultfriendfinder, although I have no experience with those.
26.2% on the 500 Question Purity Test.