Microsoft is auctioning off custom made and celebrity signed/skinned Xboxs in celebration of their millionth console being shipped.
"To celebrate the sale of 1 million Xbox 360 consoles across Australia and New Zealand, were auctioning off one-of-a-kind consoles to raise funds for the David Peachey Foundation. There will also be a unique Halo console designed by Oscar-winning, Richard Taylor of New Zealands Weta Workshop. The winning amount for the Halo console will be matched up to $10,000 by Microsoft New Zealand for a donation to Cure Kids." - Konsoles For Kids
If you don't care for the Halo-and-gunfire themed Xbox shown above, you could always bid on the crystal-studded XBox, or Russel Crowe's Gladiator-Hood Face. (He's so ANGRY.)