Noah Coad left a comment to our entry about the Snippet Compiler to inform us of a quick c# project template he whipped up for testing small bits of code in the full IDE.
From hist post: http://msmvps.com/coad/archive/2004/06/18/8408.aspx
Very often I need to test a tidbit of code, do some research on a class, etc. In fact, I was creating several times as many quick code test projects as any other project need. I used to start a Console application, change it to a Windows Application, but still needed to add namespaces, etc. So I created a custom "New Project" template for Visual Studio .NET 2003. To use, just install, load VS.NET, choose "New Project"/"Visaul C# Projects"/"Quick Test", and you're good to go.
The main goal was to minimize the time to test code. Just start VS.NET, choose the "Quick Test" project, and type code. I wanted to send output to the Trace (VS.NET Ouput Window) and have the most common namespaces already included. You can easily modify the template after it is installed to suite your own needs.
Download: CoadTools Quick Test C# Project Template (setup .msi) for Visual Studio .NET 2003