Jeff is one of the original creators of the open source farseer physics engine for Silverlight on codeplex. Andy was first to wrap the engine in reusable Blend behaviors, and now they both get to use it on cool, successful Windows Phone applications.
This video is aimed at developers so it does not do a great job at demoing the apps, for better videos of the app, check related links below. The video is part of this "An update from the Windows Phone developers" blog post; you should read that post to get most context on the casual/geeky video style.
LGs hAppiness campaign. For a limited time, if you own an LG Windows phone, you get the apps for free