Smoothly fading slideshows and hover buttons
This was done per request and while the code is not really beautiful, it works just fine.
“Fade” is a small (8kb uncompressed, 2kb compressed), standalone Javascript library which provides smooth slideshows and hover buttons, while requiring only an absolute minimum on coding knowledge. Just set a few class attributes, copy the loader code and voilà. It even degrades gracefully if there’s no Javascript available.
See it in action, along with a short introduction here.
I’d love to hear some feedback, too. 
(License is CC Attribution-ShareAlike 3.0)