Cheerios is encouraging users to create their own TV video spot and call it The Cheerios Circle of Help. They want you to help spread the cholesterol health news and in 6 weeks you could have your own TV spot.
Definitely a great usage of user generated content, viral marketing, leading into some traditional television marketing.
Check it out if you get some time at the Cheerios 4in6 TV Contest. Good example of viral social media basics.