A common type of fundraiser used by by both fraternities and sororities. "Dates" with members of the Greek organization are sold at silent auction, this is a cover for prostitution. When a naive individual wins the auction an actual date may take place, but this is usually forgone in the interest of time and money. It is an acceptable gesture to "give someone the night off" by winning them at auction but electing not to have your way with them.
Jack: "Hey man check it out, the Date a Greek fundraiser is going on again! I think I'm gonna buy me two and have a threesome"
Bill: "What are you talking about? They're auctioning off dates"
Jack: "Dates that always have happy endings"
Bill: "No way, that's a Catholic soroity"
Bill: "Ohhh. I never knew"