I used to install GXMAME for launching the MAME games in Ubuntu, but after installing Ubuntu 12.04 (64-bit) the package does not seem to be available in the Software System. I have tried Gnome Video Arcade, but it simply does not seem to work. Is there another UI that I can use to launch the MAME games?
Have you tried GMAMEUI ?
It's a fork of the defunct GXMame project.