Marriott Rewards has sent out emails this morning for the MegaBonus promotion (Register here) that will let’s you earn Bonus points with every stay. In the past Marriott Rewards would give you a free stay after two nights (up to category 4) but nowadays the promotion looks like this:
Earn 5,000 bonus points after your second paid stay
Earn 10,000 bonus points after every 10 paid nights, up to 50,000 bonus points
That’s not as generous but still worth signing up for (it only takes a few seconds).
Additionally it’s still possible to bag 120,000 Ritz Carlton Rewards points (they are 1:1 the same as Marriott Rewards points for free hotel night redemptions) with just 10 nights.
You can register here though it is said to be targeted.