These are fun:

I got them from Knom's Developer Corner, a consistent source of goodness.

Wondering why they appear to be on my desktop? Because even in Vista gadgets can be on your desktop. Just drag them there. If you use Windows+D or Alt-Tab your way to the desktop you won't see them, but bring up the sidebar with Windows+Space and the gadgets you put on your desktop will wake up too. Neat trick I learned from a Windows 7 guy .

Kate