Can I install Unity aside with XFCE and switch them as I want?

I am using XUbuntu 11.10 with XFCE and am willing to give Unity a try, but don't want to loose my well-tuned system and desktop. I don't think LiveCD is what I need: I want to try the behaviour of applications missing on it. What should I do? Can I install Unity, choose a desktop environment in some config file, reboot and get Unity, then set it back, reboot, and get XFCE?

you can install a desktop interface for example gnome3 like so

sudo apt-get install gnome-shell

and you can choose it from the login screen which desktop interface you want to use.

to install unity search for unity in the software-center or run this in the gnome-terminal

sudo apt-get install unity