Yes, just do what we've already been discussing: install one from CD, and then "apt-get install" the other one.

At the login screen (gdm or kdm), there's a little submenu you can pull up if you look closely, and that little menu lets you select the "session type". KDE, GNOME, or any other desktop you've installed (Enlightenment, XFCE, ...).

And once "logged in" and running one of the desktops, there's usually a menu item (main program menu) to "Start New Session", which lets you have *both* desktops active at the same time.

With two desktop sessions up at once, you switch between them using Ctrl-Alt-F7 and Ctrl-Alt-F8. Quite cool.

Cheeers