I can compile, get an instance and invoke a method of any C# type programmaticaly. There lots of info on that, including the StackOverflow (http://stackoverflow.com/questions/53844/how-can-i-evaluate-a-c-expression-dynamically). My problem is that I'm in the web environment and cannot save anything to /bin directory. I can compile "in-memory" as the above mentioned link suggests but then I won't be able to "unload" my custom assembly from the current AppDomain. After a while that will become a huge memory problem. Is it possible to open a new AppDomain, compile new assembly "in-memory", evaluate some expression or access some member of that assembly inside of that new AppDomain and kill that AppDomain safely when done, all that without saving anything to a hard drive? Thanks in advance for any links, suggestions, etc.