MSDN Canada runs a Gadget VS Gadget competition.
Create a great Windows Vista Gadget and you have the opportunity to win great prizes such as a Samsung 40” WideScreen LCD HD TV, Xbox 360 Pro, and a Dell UltraSharp 24-inch Flat Panel LCD Monitor!
Competition closes July 16, 2007 5:00 pm EST.
Register your gadget in the Windows Live Gallery and submit it there:
If you plan to participate, here are some links to resources that might help to distinguish your gadget:
Call a .NET class from a Gadget (without regasm.exe):
Write your gadget in C# !
To push things further you could add a spice of Silverlight in your gadget!
Gavin Gear has a great tutorial on how to create a Silverlight-enabled gadget: