Here’s a few links that are long overdue.
Jens Krause has an extension to use contrast, saturation and other color properties in Tweener. It’s based on Mario Klingemann’s ever helpful ColorMatrix class. The next version of Tweener will include similar special properties, although the internal implementation is pretty different (due to the fact that the engine also supports color matrix tweenings natively now), but Jens Krause’s work does pretty much everything one could want for color tweening.
Unic8 Studios has just posted an interactive demo of their online 3d slideshow system, called Scaena. It uses Papervision3D for some pretty nifty slideshow effects, and Tweener to help with the animation. Awesome system.
My very favorite person that I can’t really understand, Aquioux, continues to publish some very nice examples using Papervision3d and/or Tweener, and including sources when doing so. Check this one out – it’s about using bezier instead of linear paths to move glyphs around while building words.