would be the essential format. It is also recommended that you edit a "[Results]" tag into the title when the challenge is over to let people know this.
Here is a challenge template which will ensure a maximum level of efficiency in challenges. Although it is not necessary for the challenge to be considered "valid", it is recommended to be used.
Information regarding the challenge.
Difficulty: Difficulty Level
Deadline: When the challenge ends. Please include timezone in relation to GMT.
Challenge Type: Codesize, Speed, etc.
Max Entries: Maximum entries in which a user can submit.
Prize: If there is a prize, and what it is.
Platform: The platform the scripts will be tested on, such as Linux and Windows.
PHP version: The version of PHP the scripts will be tested on.
Skills: Possible skills which will be involved.
Other Notable Rules (Such as disallowed functions): Anything else the people competing in the challenge will need to know.