I read an article recently on Ars Technica about the recent design changes in Gnome. Over all it looks like Gnome is pushing forward with some interesting ideas and the article ended with a note that a live CD was available on the Gnome site that showed off the new interface. Creating a new virtual machine seems a little heavyhanded just to take a peek at the latest Gnome build so I am starting to use QEMU for that sort of thing. Here is all you need to do:
kvm -m 1024 -vga vmware -boot d -cdrom ~/Downloads/GNOME-3.4.iso
This kvm command comes from the qemu-kvm package which would obviously need to be installed. You may notice it resize a bunch of times before it settles down. This is a known bug, that is easily worked around by just giving it a few seconds to work itself out or resizing the window yourself. Anyway, that aside this a pretty useful way to test a live CD. Enjoy!