CS-Script looks very similar to the O2 Scripting Environment.
Here is an Code Project article that provides more info on CS-Script: http://www.codeproject.com/Articles/8656/C-Script-The-Missing-Puzzle-Piece
Code Project is a great reference, and I really like how they allow tools to write technical articles in there. Maybe it is time to write a couple O2 articles and it put in there :)
UPDATE: if you are interested in C# Scripting environments, take a look at O2's C# REPL Script Environment