Whats the difference between LINQPad 2.x and LINQPad 4.x?
LINQPad 2.x runs on .NET Framework 3.5; LINQPad 4.x runs on .NET Framework 4.0. The latter allows you to access .NET 4.0 features such as PLINQ, TPL, Entity Framework 4.0. It also lets you reference assemblies that you’ve built in Visual Studio 2010. You can run LINQPad 2.x and LINQPad 4.x side-by-side. They will each update themselves independently.