It's for the Ides of March and runs 1-15 March. Lucky winners will get 16 books--one from each of the participating authors--and we're giving away one set per 500 entries. The contest is open to US/UK and Canada.
Here's the link to the website where people can enter:
The deal is that all entrants agreed to be added to authors' mailing lists (they can always unsubscribe later, naturally.)
Here are the books/authors: