Marriott has come up with a real Black Friday Sale – 30% off for Marriott Rewards Members.
Book two nights or more by November 30 at a participating hotel
Stay between December 11 and January 17, 2016
Hurry – availability is limited; advance purchase required
The resulting rates are indeed discounted a full 30% for most properties. The are pre-paid rates (which allow a 24 hour cancellation when booked at marriott.com).
Most properties in the US, Canada and Caribbean seem to participate. Book until November 30th to get the deal on marriott.com.