It's the one night that everyone goes out and drinks excessively. Because many inexperienced drinkers can not handle excessive alcohol, it is often referred to as "Rookie Night"
Someone who uses roofies to get someone else to sleep with them. GDI's and haters of greek life like to accuse fraternities of having such people in their houses- as a way of undermining the popularity of the fraternity on campus
Person 1: That fraternity is sketch, They have been known to roofy freshmen girls.
Person 2: Seriously!? who are the roofers in the fraternity?