I needed to do some live debugging on TeamMentor, so I just added a simpler version of the CSharp-REPL Web to it.
To access it, go to the TeamMentor's Control Panel, and click on the C# REPL link:
which should look like this:
What is really powerful is that we have full access to the live HttpContext and (for example) the HttpRequest objects:
And if you are running TeamMentor locally (i.e. from Cassini) you can also open an O2 Script_Me C# REPL window like this:
Which will give you a much more flexible and powerful way to script the ASP.NET Http pipeline: