Originally Posted by MDtR-Chicago

Marriott has a long-standing program where existing members can refer new members. The new member gets 2000 points for each of his/her first 5 paid, points-earning stays within a year. The referrer gets the same bonus.

There's a sticky thread on the program in this forum.

(I should note, tho, that there is an offer floating around for new members to sign up without a referral, and the bonus there is a Cat 1-5 cert after two stays. That may be a better offer for many.)