dynamic class

Question

Ok, this is probably going to sound a bit strange and I am not sure if it is possible with C#, but what I want to do is develop an application that allows the user to write a program/class and then run it, the program/class will only need to use a set or predefines classes. So is it possible to create compile and run something for from with in a c# application, without having to redevelop parts of the IDE? Many thanks for any help, and I hope this makes sense? Craig