Is there any documentation/support for Google Gadget type of Widget? Or does anyone in the Community have experience using this Widget?
A Gadget is just a pice of xml code, and the Gadget widget makes it really easy: you just create a new Widget, select Google Gadget type, and follow the steps until presented with a box were you’re expected to paste the code.
Paste it, save, and then you have a widget ready to use like any other.
The documentation on how to get the gadget code is available through Google itself. For example, here.