1-2-3 is a game of logic that pits you against the machine. The game's "logical thinking" is hardwired wired without using a microcontroller. It's all diodes, transistors and LEDs.
Easy to play. Not so easy to win. You play by moving a peg along a path of holes. Players move alternately, and on each turn a player can move the peg 1, 2 or 3 spaces (hence the name). The player who moves the peg to the final hole is the winner.