LINQPad is probably the most useful mini-IDE that I've ever used for .NET development and I employ it every single day for prototyping, scripting and experiment

LINQPad is probably the most useful mini-IDE that I've ever used for .NET development and I employ it every single day for prototyping, scripting and experimenting. Joe Albahari developed it and he's renowned for his C# .NET expertise, so you're in great hands with this utility.