There are presently two major chatterbot contests which utilize the Turing Test as the determinant - the bot which most closely comes to passing (or does pass) the Turing Test is deemed the winner. These two contests, the Loebner Prize for Artificial Intelligene and the Chatterbox Challenge have been around for several years and are bound to become more popular as technology improves over time.

The Loebner Prize for Artificial Intelligence is described as:

The Loebner Prize is an annual competition that awards prizes to the Chatterbot considered by the judges to be the most humanlike of those entered. The format of the competition is that of a standard Turing test. In the Loebner Prize, as in a Turing test, a human judge is faced with two computer screens. One is under the control of a computer, the other is under the control of a human. The judge poses questions to the two screens and receives answers. Based upon the answers, the judge must decide which screen is controlled by the human and which is controlled by the computer program.

The Chatterbox Challenge is composed of several tests and categories, with the 'conversational' test at the heart of the contest:

The bots will be asked a set of 10 questions. Each question will be spelled and phrased exactly the same way. This is to insure that each bot gets a similar conversation. The questions will be asked within the framework of a conversation. The judges will steer the conversation via the questions asked but will also follow the lead of the bot..

Upcoming Loebner Prize Contest:
Next occurs on October 12, 2008 in Reading, UK, however the entry deadline has now passed.  Full rules.

Upcoming Chatterbox Challenge:
Next occurs in April 2009, with entry deadline of March 15, 2009.  Full rules.