If you bounce it into the cup, the other guy has to drink it and retrieve the quarter. Quarters was probably the main drinking game in the early 80s, before Beer Pong came along, and I played it many a night with Georgetown Prep guys that went to my school. It may have come from there, we didn’t play it at my high school in Missouri.
You may not have had any ping pong balls, but everybody’s got a quarter.