GWT Widget: Rolodex
Right now the animation images are generated by hand, but with a little bit of Java 2D, this can happen at compile time. You can kind of see some of the issues here of Flash v.s. DHTML. Flash has all sorts of image transformation goodness, while DHTML is a little handicapped here. You could use something like Reflex instead of compile time image transformation, though I haven't tried out how well it performs when animating.
Anyhow, nice work Chris. It's nice to see folks pushing the boundaries of what one can do with DHTML widgets.