Languages

• PowerShell
• Nemerle
• IronPython
• Boo
• SharpSmalltalk
• Phalanger
• and others...

Unit testing

• xUnit.net - new'n'shiny
• NUnit - mature but not actively developed
• ...and Visual Studio 2008 Professional

Tools

• Lutz Roeder's Reflector for .NET - the ultimate decompiler with lots of addins
• LINQPad
• PostSharp - aspect oriented programming for .net
• SharpDevelop - open-source IDE
• Expresso - Regular Expression editor and tester

Sites [en]

• CodePlex - open source project repository
• pinvoke.net - Win32 API PInvoke declarations wiki
• CodeProject
• C# Friends

Sites [cz]

• aspnet.cz
• vyvojar.cz

WPF

• WPF Draw Tools