Using an older window manager is usually a case of installing its package and adding it to a file executed by your display manager. I don't have much love for the old window managers, but some of the newer ones are quite nice.

As for the old window managers (and applications) themselves, I would imagine they are still bundled with Debian. Now that Debian allows non-open drivers in their official installation media, I'm tempted to try installing it to relive some of that X11 nostalgia. (I have fond memories of xv, xfig, and such.)