Hi!
I want to introduce
http://www.bitcoinauction.us/It works like an auction, but there is a tiny difference:
You bid bitcoins to get some more bitcoins as a prize.
Even if you do not win the auction you won't get your bitcoins back, because they are used to pay the prize.
While the auction is running you are able to send additional bitcoins to increase your bid.
Good luck!
Feedback and suggestions are welcome.