Formally Konfabulator, it runs what are called Widgets, which are created by ordinary people using fancy JavaScript, Photoshop, GIMP, and the like. There currently 3,000 widgets out now, give or take a few 100. It has everything, including a Homeland Security terrorist threat level chart, so I can see how likely I am to die today. It also takes up rediculessly LOW processor power, especially if it's in the Heads-Up-Display. I can even access UD without having to open to a browser! Lazy!
If any Yahoo! Widget Engine users check this out, go ahead and post your tweeked-out desktops. To make a screenshot...

+Windows-hit "Print Screen," left of scroll lock (prt scr).
Hit paste on a document, the picture will appear.
Drag picture to desktop, file will be created.
Open file with Microsoft Picture and Fax Viewer.

Donno for Macs, I don't have one...
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