The stop sign game is a game where people are in a car driving around, and when you see a stop sign, you must touch the top of the car. Last person to touch has to take off an article of clothing. Shoes are automatically off, and both socks count if you are wearing them. Usually played in the dark. First person with everything off loses.
"Hey you wanna go play the stop sign game?"
"Yeah as long as we get that hot girl to lose everytime!"