Two parts to this story:
The first is about how social network buttons can be implemented in third-party applications in Windows Phone 7. This is something that Android and the iPhone do quite well--they allow you to share your media, scores, basically anything, with social-networking sites. The app can call up the API and it then allows you to send it via that app to a service like Twitter.
Silverlight developer Ian Walker shows how this can look when implemented in WP7. While the details of how this is done is of interest only to the developer, seeing what it'd be like is what most of us may be curious about. We just hope other developers to do the same.
The second part involves two Silverlight games (by the same Ian), both being ported to WP7. The first is 'Nuke Your Office' which combines Bing maps with, well, simulated mass annihilation. Sweet. The other is a puzzle game Back to the one with nukes though, you can play it right now at work and vent your frustrations. Not sure how much-repeat value this will get, but if you're bored now, here ya go...