Separate monitors with separate keyboard and mouse input?

So I was wondering if it would be possible using Xfce and without virtual machines to essentially make one computer act as two by having two monitors with different workspaces and separate keyboard and mouse input. For example one person could be playing counter strike on one monitor while the other one worked on the other one and neither of them would notice that the other one was on the computer.

I don't know if this is possible, or if it's easy to set up but the concept certainly seems interesting.