Just saw this one on Marriott.com today...also posted in promotional codes thread as it looks like a public offer.

Get up to a $50 Amazon.com Gift Card when you stay the weekend at any participating Marriott and pay with your Visa card. Book Now.
Your weekends just got more fun!
For a limited time only, Marriott and Visa invite you use your Amazon.com Gift Card on a huge selection of books, electronics, DVDs, software, apparel and much more. Simply spend a weekend at participating Marriott Hotels & Resorts, JW Marriott Hotels, Renaissance Hotels & Resorts and Courtyard hotels, pay with your Visa Card and get up to a $50 Amazon.com Gift Card*.

* Get one voucher for a $25 Amazon.com Gift Card claim code per night for up to two nights on weekend stays at Marriott Hotels and Resorts, JW Marriott Hotels, and Renaissance Hotels and Resorts
* Get one voucher for a $15 Amazon.com Gift Card claim code per night for up to two nights on weekend stays at Courtyard hotels

Deal Details:

* Book between April 13th and May 3rd 2009 for weekend stays between April 16th and June 14th 2009
* Use promotional code OTP to book now
* Present your Visa card upon check-in to receive a voucher for an Amazon.com Gift Card claim code
* Log on to the provided URL and register for your Amazon.com Gift Card claim code
* A link to receive Amazon.com Gift Card claim codes will be emailed to qualified guests within 5 business days after online redemption
* Offer valid in US and Canada

Time is limited, so book now:
To reserve your weekend, book here or call 1-877-MARRIOTT and request code OTP.