The cups and balls is a classic performance of magic with innumerable adaptations. The effect known as acetabula et calculi was performed by Roman conjurers as far back as two thousand years ago. One popularly circulated picture, thought to date from 2500 B.C. from the walls of a burial chamber in Beni Hasan, Egypt, shows two men kneeling over four inverted bowls. It was taken by early Egyptologists Wilkinson and Newberry as evidence that the cups and balls effect, or its related deceptive gambling game, thimblerig, possibly dates back to Ancient Egypt. Because of its context, modern Egyptologists regard the image as a game using pots or cups but details of the game are unknown. The illustration is unique in ancient Egyptian art, so whether or not the game utilizes sleight of hand trickery may never be known unless a future discovery produces a similar image in a more explanatory context.
The most widely performed version of the effect uses three cups and three small balls. The magician makes the balls pass through the solid bottoms of the cups, jump from cup to cup, disappear from the cup and appear in other places, or vanish from various places and reappear under the cups (sometimes under the same cup), often ending with larger objects, like fruit, or vegetable, or even baby chicks appearing under the cups.
A typical cups and balls routine includes many of the most fundamental effects of magic: the balls can vanish, appear, transpose, reappear and transform. Basic skills, such as misdirection, manual dexterity, and audience management are also essential to most cups and balls routines. As a result, mastery of the cups and balls is considered by many as the litmus test of a good magician. Indeed the late magic authority, John Mullholland, wrote that no less a person than Harry Houdini had expressed the opinion that no one could be considered an accomplished magician until he had mastered the Cups and Balls. Professor Hoffman called the cups and balls "the groundwork of all legerdemain".
Instead of cups, other types of covers can be used, such as bowls or hats. The classic shell game con is a rogue-variant of the cups and balls.