I've just been sent a new Windows Vista sidebar gadget produced by Universal Music - see http://www.umusic.co.uk/gadget/. Very cool, I love it.
If you have Windows Vista give it a whirl and let me know what you think.
You can write sidebar gadgets in C#. Admittedly, it's a bit of a fiddle since they're hosted in a browser-like host.
You can actually use any supported scripting language, including VBscript. Just make sure that you declare it as a VBscript in the gadget.html file, such as:
Again, you can specify whatever script type you want as long as it's a supported scripting framework; js, vb, c#, etc.