Santa was kind enough to bring my daughter Karaoke Revolution, and we've been having a ball with it. But, the microphone looks like it belongs to a 70's cassette recorder. (It's the same style as the Mario Party mics, just black.)
I saw that Konami made a pretty nice looking mic for the PS2, but after Googling the crap out of it I couldn't come up with anything else for the Gamecube.
It's... interesting, but not in a bad way. I'm a Star Wars nut, so I'll buy anything they slap the logo on. Which coincidentally enough means I'll be broke coming up what with Jedi Knight 2 and Bounty Hunter coming out for the Cube.