I did a Facebook iPad giveaway contest several months ago. The campaign was quite successful. After that campaign, our Facebook page is more active.

This is our Facebook page:
https://www.facebook.com/comm100

Here is the screenshot of our contest page:

The url of the content landing page is:
http://www.comm100.com/landing/winipad2.aspx

The ways we let people know about the contest are:
1. Web site
2. Our own blog
3. Our social channels, like Facebook, Twitter
4. Newsletter to our subscribers

Lesson learned: If we integrated Twitter together with the Facebook campaign, the result could be better.

Just a quick share. Thanks.