HowGoodInBed.com: is a web front end to a neural network. Every piece of data you add trains the network a little bit more.
So what does it do? It tries to correlate externally observable factors (such as age, height, build, hair, skin colouring, social behaviour, chattiness, happiness, physical activity level and intelligence) with sexual attributes (such as viviaciousness, willingness, location, adventurousness and skill).
You can enter the network either way – by describing someone you know to get an estimate of their bedroom rating, or vice versa – by describing what you want it will tell you the sort of person to look for. And of course there is a section to input your rating of real people you know to train the network a bit more. Try it and see!