Mouse Trap (originally titled Mouse Trap Game) is a board game first published by Ideal in 1963 for two to four players. The game was one of the first mass-produced, three-dimensional board games.^[1] Over the course of the game, players at first cooperate to build a working Rube Goldberg–like mouse trap. Once the mouse trap has been built, players turn against each other, attempting to trap opponents' mouse-shaped game pieces.

The basic premise of the game has been consistent throughout the game's history. However, the turn-based gameplay has changed somewhat over the years.

The original version, designed by Hank Kramer of Ideal Toy Company, allowed the players almost no decision-making, in keeping with other games for very young children such as Candyland, or Chutes and Ladders (Snakes and Ladders). In 1975, the board game surrounding the Mouse Trap was redesigned by Sid Sackson, adding the cheese pieces and allowing the player to maneuver opponents onto the trap space.^[2] A modified version was released in the United Kingdom in 2004, featuring three mousetraps (with a specialized trigger that can triger one of them at random) and a completely different board and plastic components.^[3] Characters from the Elefun and Friends universe were added to a new version in 2014.^[4][5]

Each player is represented by a mouse-shaped game piece which travels along a non-continuous, roughly square-shaped path around the game board from the start to a continuous loop at the end. The path is segmented into spaces, some of which are marked with instructions, and "build" spaces that are marked simply with numbers ("2", "2-3" and "2-3-4").

Each player attempts to trap opposing mice using the game's complicated mouse trap, which is built upon the board during the course of the game. The trap begins with a crank which turns a set of gears. This begins a series of stages which ends in a cage being lowered over the "cheese wheel" space on the board, which is one of six spaces in the ending loop of the game path.

Players roll the six-sided dice in turn-based play, and move their mice the number of spaces rolled. A player who lands on a "build" space that corresponds with the number of players in the game (e.g. only "2-3-4" spaces for a four-player game) must build the next unbuilt piece of the mouse trap, and take a piece of cheese, represented by cheese-shaped tokens. If the players reach the final loop of the board, they continue around it until the game ends; each "build" space in the loop requires a player to build two pieces of the mouse trap, and take two pieces of cheese.

Another space on the board is the "turn crank" space. Once the mouse trap is built, if a player lands on one of these spaces while there is an opposing mouse on the "cheese wheel" space they must turn the crank to start the mouse trap. Should the trap successfully run its course and cause the cage to fall onto the board, any opposing mice on the space are out of the game. If there are no opposing mice on the "cheese wheel" space, the player may trade one piece of cheese for the opportunity to choose an opponent who is not on a "safe" space and roll the die to move their mouse; this may be repeated during the same turn so long as the player still has cheese pieces to spend. If the target mouse is moved onto the "cheese wheel" space as a result, the crank may then be turned. Once there is only one mouse left in the game, its owner wins. Other spaces require player to move mice in a prescribed manner.

The mouse trap in the game has never changed in operation, though the color and shape of some pieces has been slightly modified over the years. There are several stages which form the mouse trap, and most stages are composed of multiple pieces. A 1990s ad campaign for the game involved a song which listed most of the stages of the mouse trap.

In a proper operation, the player turns the crank, which rotates a vertical gear, connected to a horizontal gear. As that gear turns, it pushes an elastic-loaded lever until it snaps back in place, hitting a swinging boot. This causes the boot to kick over a bucket, sending a marble down a zig-zagging incline (the "rickety stairs") which feeds into a chute. This leads the marble to hit a vertical pole, at the top of which is an open hand, palm-up, which is supporting a larger ball (changed later on to a marble just like the starter one). The movement of the pole knocks the ball free to fall through a hole in its platform into a bathtub, and then through a hole in the tub onto one end of a seesaw. This launches a diver on the other end into a tub which is on the same base as the barbed pole supporting the mouse cage. The movement of the tub shakes the cage free from the top of the pole and allows it to fall on the mouse.

There are several points at which the mousetrap can commonly fail. If not built level, or if kicked too hard, the following scenarios can happen.

The game designer Marvin Glass (and his company, Marvin Glass and Associates) refused to pay licensing fees or royalties to Rube Goldberg, despite Marvin acknowledging being inspired by Goldberg as well as the clear similarities between the game and a Goldberg drawing. Glass went on to develop two less well-known games based on Goldberg designs, Crazy Clock Game (released 1964) and Fish Bait (1965), neither of which credited Goldberg's influence. Elderly and near retirement, Goldberg declined to take legal action against Glass because inspiration and ideas are not intellectual property that can be protected with a copyright, trademark, or patent, and chose to sell licensing rights for his drawings to another toy company, Model Products, to help secure the rights to specific intellectual property that he owned and for which he might receive royalties.^[6]

Mouse Trap was adapted into a game show which was featured on the British children's television show Motormouth.^[7][8] A life-size board game was created and the child contestants took the place of the mice.