http://www.xubuntu.org/

http://lxde.org/image_galleries/screenshots

http://en.wikipedia.org/wiki/FVWM-Crystal

But they are available from download using Synaptic within Ubuntu. You can
select on restart which GUI will be default. Look for Metapackages, or search
for Xubuntu, Lubuntu or that last one. I like LXDE because it also gives you
Openbox, espically for older less RAM systems.

Sometimes in the past when a Ubuntu Live CD would not boot on a computer, I'd
try the other Ubuntu Live CDs and load the GUI that I wanted this way.