MGM will not get your whites whiter or your colors brighter. It will, however, sit there and look spiffy while sucking down a major honking wad of RAM.
The Moaning Goat Meter is, as described in the intro, the "the ultimate sixty-ton cast iron lawn ornament for the desktops of today's hacker set." If you check out the screenshot, words can't really describe how stupid the little fish is while it spins around for no reason. It's a load meter - it analyzes how much memory your computer's using, how efficient your CPU is, how much you have left in your battery (on a laptop) - it's basically like all the lights on your dashboard, except for your computer- if it was designed by some bizarre crossbreed of Hiro Protagonist, Liberace, and that guy responsible for the Edsel. Also, the FAQ is one of the funniest things I've read in weeks, and is responsible for the phrase "my hard drive is swapping like a wounded moth!" entering the Linux Lab vernacular.