Challenge Coin, Military Challenge Coin. Created for members of a military unit, a custom-designed medal of roughly silver-dollar size to be carried by members or supporters of that unit. Originated by military unit commanders who wished to increase morale, patriotism, unit esprit and honor military service in that unit, the medals are carried as a pocket piece. Some even attribute good luck to the piece, particularly when carried onto the battlefield. The design is often simple, although it may appear in unusual shape, and often with a colorful enamel. Some date the origin of challenge coins to as early as World War I but their use has dramatically increased by the military in the last quarter of the 20th century. In addition to unit challenge coins, some individual personnel have personal challenge coins made for distribution to fellow service members, and perhaps others.

The “challenge” is for those in a bar or club where someone reveals their “coin” by raising it in the air or tapping it on the bar or table for someone else known to have such a medal to produce theirs within 60 seconds. If not that person has to buy the drinks. If either one drops his challenge coin he must buy drinks for all who hear it drop.