2.DinnerNow
It offers a marketplace where local restaurants foods
are ordered by customers to bring food to their
home or destination.this application guide you on
how to build a connected application by many
microsoft technologies like IIS7,ajax extensions,
linq and others.
visit dinnernow.net for the application.

3.dropthings
Its a ajax portal of web 2 supporting widget
based website,content drag & drop,open API for
the widgets.
visit the following websites to learn more
about it-
codeplex.com/dropthings

Find more in microsoft website.also follow my
next posts.