Not surprisingly, 21st birthday cards are being handled in a number of different ways. Some folks print the cards themselves on a color printer. Others use professionally designed and printed cards. Some add an information insert on titrating your BAC, recognizing alcohol poisoning, alternatives to drinking, etc. Several campuses are using B.R.A.D. cards.
Some programs involve peer educators in sending the cards.
Registrar's offices were mentioned twice as the source of lists of students about to turn 21. A couple of folks are evaluating their 21st birthday card programs. I hope this helps. Thanks again to those who responded.