Re: adding a page
Those links you see are hard coded in the home theme. You can check out my beta site where I have started to play around with adding more links and doing some fun stuff with the standard theme.
I’m a little confused about the widget part? If you are thinking about building your own …. (shopping cart, arcade, radio station), then you should be able to follow any of the standard examples floating around about how to build custom pieces, and add a link to that custom piece in the home theme.