This is a set of C# extension methods (compatible with C# 3.5+) that make the language a bit more friendly. It's not a "Utility Belt" per se - just some object extenstions "designed to increase developer happiness".
These extensions are what I use in the WebMatrix videos on Tekpub.
Drop the code file into your app and change it as you wish.
Have a look in the files - see what's there. Strings, Dates, Regex, File IO and Validations - stuff you write every day.