how to execute a viral website contest?

[jspinx]

I have a website that sells books and other military gear. I have a few hundred dollars in free products to give away. I would like to do it in a form of a contest. I am wondering what I can do that is easy to execute but drive traffic to the site and get good backlinks and social media coverage.

[nineglasses]

I would use facebook and twitter: For facebook, I would make a "likes" contest--like or share my url and you could win such and such. For twitter, I would do the same but with tweets.

These two are easy, you could also do wordpress and other blog posts, but it gets complicated, unless your require them to send you a snippet of the blog post.