Tic Tac Toe

Pentago might remind you of Tic Tac Toe (called Noughts and Crosses in England). Though this child's game usually ends in a tie when undertaken by experienced players, it's considered by many to actually be the first game played on a computer. The EDSAC machine at Cambridge University was one of the first programmable computers, and in 1949 a Ph.D. student wrote software to allow it to play Tic Tac Toe [source: Adit].

All you have to do to win Pentago is place five marbles in a row on a 6 by 6 wooden grid, which is actually made up of four smaller 3 by 3 grids. Sound easy? There's a mind-bending twist to this game that makes it much more complex. After placing a marble, a player gets to twist one of the four smaller grids 90 degrees.

Few strategy games have rules that are so simple and play that's so subtle and quirky. You set your strategy, but your opponent can thwart you by simply twisting a section in a way you didn't expect. All kinds of traps and feints are possible.

The game, which retails for about $25, has a classic look, with a natural wooden board and white and colored marbles. Introduced in 2004, it has won several "game of the year" prizes [source: Pentago].