The US’ NFL are runnng a competition this year to have their Superbowl ad created by a fan.   Interestingly, they are not jumping onto the ‘upload your video’ bandwagon but making peotential ad writers turn up and audition in person. (although, given the rules of the pitch, I think they should have allowed video presentations)
Auditions are running at three locations in the US, 2 days for each, and they are planning on seeing 2000 people at each location.  Everyone gets 90seconds to make their pitch and gets scored on

• connection to NFL football
• commercial appeal
• originality and creativity

The tie breaker is based on emotional connection.   Each audition will be taped and you have to agree to allow the audition tape to be placed on the web for viewing and voting.   The NFL are not paying anything for people to travel to the auditions and are not paying people for their time or creativity.  But they are going to be taking all rights to the concept that you show them, regardless of whether it gets picked.   So by travelling at your own expense to the audition, waiting for up to 2 days in the hope of being seen, the NLF take the copyright to your idea just by you standing up for 90seconds.

Furthermore, by being videotaped you are allowing signing away your right to dignity:

I understand that, as part of the Contest, the public may vote on my Concept after viewing a video of my participation in the Contest over on the Internet or otherwise. This may result in the public disclosure of my appearance, name, likeness, voice, conversation, biographical data and other information about me, including that which is of a personal, private, embarrassing or unfavorable nature, which may expose me to public ridicule, humiliation or condemnation. 

Even after all of this, they reserve the right to not make or show any of the ideas that have been presented, even though they now own them for all time.  Crowdsourcing at its worst.