Is it possible to create plug ins for the Xbox 360 dashboard?

I was looking to turn the 360 into the hub for the family. So you could for example turn the xbox on, and there on the dashboard see all the families calendars merged, todo lists, grocery lists, birthdays etc.

I can't see anybody talking about plugins for the dashboard around the net so I'm guessing you can't, but thought I'd check. Next option will be something like a net top running in the family room, but that means 2 devices then, one for gaming and one for the family functions