Each month christianaudio.com gives away a premium audiobook download for free. The free download for the month of November is Calvin: Of Prayer and The Christian Life by John Calvin. (Click the banner to go to the download page.)
After creating a free account and logging in, click 'add to cart' on Calvin: Of Prayer and The Christian Life by John Calvin and then proceed to 'checkout' as if you were paying for it. Then you will be able to use the coupon code NOV2008 to download the audio book for free.