This is ProjectM, the awesome audio visualiser. It allows you to play with the popular Milkdrop visuals of which there are hundreds available in the forum but don’t appear to be in the officials repos yet, although some bits are already part of Totem. Ubuntugeek has provided a tutorial on how to go about compiling the latest release. Be warned, it might not be plane sailing, but there is plenty of help in the Ubuntu Forums topic. And we probably have to campaign if we want to get the somewhat psychedelic audio visual project a proper ppa. Then again, why not hack Totem? The player could do with a better Milkdrop plugin system.
UPDATE: If the latest version doesn’t work, and there are reports of there being trouble with the code repository. Try an earlier version. This works just fine in Lucid and Karmic