An architecture or patterns for gadget-based applications

Hi all,

Before saying anything,please forgive me if here is not a right place
for such a discussion.
BTW, I want to build an application with gadgets which every gadget
can do a distinct job but all form an application, like google desktop
or vista's or yahoo's widgets.

Now The problem is the best way to do that. I Know plugin-based
architecture but any suggestions for architecture or patterns that can
be use in these kind of applications?

Thanks a lot.
Behzad