ContestMachine
Roll your own contest or giveaway. No longer in business.
http://contestmachine.com
ContestMachine is a web service that makes running promotions from any website easy. The service allows clients to run a contest or giveaway from their blog or website and handles the rest of the details, like collecting submissions and contacting winners. The service also allows clients varied options, like choosing entry requirements, start and end times, and the addition of prizes.