This might actually be the best captcha idea I've seen in a while.

It's certainly the most enjoyable.

http://www.hotcaptcha.com/

It actually makes sense too; the level of programming required to analyse what shapes/tones/poses etc makes someone "hot" is way to far advanced from current levels, so this one might actually be good for a while.

Of course, it may start getting offensive when the system keeps repeating it's captcha requests to you over and over ... in which case you probably need to get out much.