Been digging into some of the classes in Microsoft.Web.Helpers. Lots of interesting things there, the basics being classes that inject scripts and HTML into your website for lots of popular activities and services out there. Many that you would expect (Bing, XBox gamer tag, File Upload) A few surprises as well -- classes for Google Analytics, Recaptcha (a Google service) and a Flash video player. Some screenshots:
Kinda trippy but kinda great too.