8th grade basketball -- Not a team sport jock here, went out for the team to try and fit in.
The one basketball game I played in, a teammate passed the ball to me, and I started to move the ball TOWARD THE WRONG BASKET!! (I knew almost nothing about the sport!) Someone on the team yelled, "YOU'RE GOING THE WRONG WAY!" I quickly reversed court, and passed the ball to someone who knew better.
Actually, now that I think about it, it was more humiliating than funny.