If you happen to have an Xbox360 HD DVD drive or picked one up during the bargain bin phase when they were going for $50 [or less], here's an extensive list of what you can do with it.
1) Playing DVDs, since it works better than the drive in the 360.
2) Playing Transformers over and over and over in HD
3) Convince dumb friends its the new mini-xbox
4) Book-end
5) Play toy for the dog
6) Drink holder
7) Foot rest
8) Playing movies on that old X360 you have whose drive stopped working 2 days after the warranty expired
9) TV series marathon tool, so your X360 can hold 2 episode discs at once
10) Sold on Ebay in 10 years as a 'rare player'