I do a 3 day charity ride every September. The team that I ride with started calling out "POLE!" while riding on the Cape Cod Rail Trail. They use these cement filled yellow posts at road intersections to keep motor vehicles from turning onto the rail trail. We now have a teammate with the nickname "Ping", because despite our warning calls, he smacked right into one. Granted, we had consumed A LOT of tequila the night before, but the rest of us managed to avoid conducting any physics experiments that day. He was okay, and so was the bike. We didn't want to laugh, but we had to.