Everybody likes a treasure hunt, especially when there are cool prizes involved. Twilight Times Books is running a treasure hunt contest during the month of September with prizes like a Kindle Fire, a B&N Nook Color, a Google Nexus Tablet, and baskets of books (print and electronic).
PLUS there’s a foghorn contest. If you tweet or post about the contest somewhere, you get points you can redeem for books.
For the treasure hunt, you just have to go to various Twilight Times authors’ web sites and find the jewel hidden on their front page. I’ll get you started with the Alexandrite on my front page.
Good luck!