Bidding on things from eBay is a daily occurrence for some people out there. The thrill of winning, or losing, and sometimes even getting something pretty cool out of it, too, is all reason enough to keep trying your luck in the global auction. In this case, you could start bidding on a replica helmet from Halo: Reach, worn by the knife-wielding character Emile.
The proceeds will go to Child's Play, as well as the Brian Wood Memorial Trust, so you can safely say that the winning sum will be used for a good purpose. The helmet itself was sculpted by Daniel Yuan of the 405th Infantry Division, but it's probably not one helmet that you'll want to wear if you want to actually see what you're doing. The replica is also signed by over 20 Bungie employees, so it's obviously a collector's item.
If you're interested, you'll need to hurry up and start bidding. As of the time of this writing, the eBay auction was at $475, and is scheduled to run its cource by 9:30PM Eastern time. So, get to bidding!