Free Apple Air laptops contest

I've ordered two Apple MacBook Air laptops to give away at Mahalo in some type of a contest. Looking for ideas of how to give away the laptops that generate MORE value for Mahalo then the actual ~$2,000 in cost associate with the laptop.

Some of the (obvious) key metrics we follow at Mahalo are:

1. Number of search pages created
2. Number of people signing up for Mahalo (i.e. registered users)
3. Number of user links submitted and added to Mahalo
4. Number of links *accepted* to Mahalo pages
5. Pageviews
6. Unique visitors
7. How To articles created

Does anyone have any ideas!??!