1. An evening in which you go out to a party or the bars, shamelessly sing your heart out on the karaoke stage, then walk home barefoot only to find that you are locked out of your house, but are too afraid to wake up your roommates (who have exams the next day), so despite the freezing temperatures, you fall asleep on your front porch.
2. Any truly crazy college night that provides you with several funny stories to tell the next day.
Since college is going to be over before we know it, we have to have as many Sleep on the Porch Nights as possible before we graduate so that we have stories to tell our grandchildren.