Picbreeder
nbenko1.github.ioVery fun. My attempt to "breed" a face:
https://pasteboard.co/V8BwJFPuCVil.png
The experience of finding a trait that you want and then working to preserve it was interesting.
Notice this is a reimplementation in js. It's hosted on GitHub with no db. The original was a bit more sophisticated, with a lot of collaborative breeding stuff enabled by server-side code.