I hardly ever see stories about how people have chosen the Microsoft stack to build high traffic websites but apparently Plenty of Fish created one using running ASP.NET, IIS, and a 64 bit Windows Server 2003.  One man shop too, read up on the Plenty of Fish architecture on highscalability.com.

RishText Builder is a cool library for creating RTF formatted strings; but what's REALLY cool is the ascii art found in the source :)