Domers, but certainly everyone...I'll start...
Freshman year Spring Break...a bunch of us headed south to Ft. Lauderdale...heard about a huge beach party one evening...showed up only to find that we couldn't get in, because it was only for "Greeks" and ND didn't have any Frats...'chastened', when we returned to campus we decided to 'create' our own Fraternity using letters that did not exist on any Greek listing...showed up the next year with 'official' looking cards (just like our friends' from legit frats) and T-shirts sporting our letters...got in and had a great time!
(btw...still have my shirt...and the card (somewhere))!