Use C# interactive in Visual Studio to experiment with your code on the fly
I needed to quickly test a regular expression, and the new feature of Visual Studio 2015 came to the rescue: C# Interactive
Published:
You will find this under View → Other Windows → C# Interactive
In my case I wanted to test how the Regex.IsMatch() method handled strings that were null or empty. Note that I had to import .NET's RegularExpressions library.