Code Test Bed

Something that’s lightweight that will let you code just the stuff that you need to try and nothing else.
With it, you can code in C# or VB.NET and the utility will wrap it all together into an assembly that it will execute for you, allowing you to show off your genius.
Fire it up and you'll see the screen above (but without the user entered source).

You can just start typing in your source. There’s no intellisense, no code colorization, no auto-formatting, no pretty printing, no nothing. Bare bones, enter your code here.