LINQPad License
LINQPad is free to download and use.
LINQPad is not an open-source product and the source code is protected by standard copyright laws. Nonetheless, you are free to disassemble the executable to satisfy your curiosity (and for this, I suggest Lutz Roeder's .NET Reflector).
The author provides no warranties, and accepts no liability for direct or consequential damages.
The code samples from C# 3.0 in a Nutshell are © O'Reilly Media Inc.
© 2007 Joseph Albahari