Wallamoppi is a fiendishly fast dexterity game. Players first build a pyramid using the light and dark wooden discs; this is the part of the game that takes the longest.
Once the pyramid is finished, one player drops a marble into the game box -- which very cleverly doubles as a timer with wooden ramps to carry the marble. Before the marble reaches the bottom, the other player must pull one of his discs out of the pyramid and stack it on top without causing the middle tower to collapse.
For 2 players, ages 5 and up, about 5 minutes per game.