Cairo-Dock is an animated launch bar similar to SimDock or AWN. You can use it to launch applications and utilize small applets that live on the bar. It lacks some of the visual effects provided by AWN, but it my experience it runs a little faster.
This application is an continuation of the abandoned GNOME-Dock project. According to the Ubuntu Wiki:
[...] it is compatible with Beryl, Compiz, Metacity+xcompmgr and probably KDE since Kwin now manage composite display.
There's definitely a lot of eye candy infused into this bar. It has animated icons, a 3D plane with reflection.