Mastermind has to be one of the all-time classic guessing games, and it makes for a great way to waste a bit time on a long journey.
In case you don't remember, the object of Mastermind is to try to discover your player's secret 'code', which is made of a sequence of four different colors. In order to make a guess you need to place your colored counters onto the board in the order you think they appear on your opponent's code.
Your computer opponent will then indicate whether you've got the colors in the right places by using a sequence of pins. You must guess your opponent's code within 8 moves or the game is over.
This all seems a little convoluted, and I guess it is, but that doesn't stop Mastermind from being a really addictive challenge. The graphics aren't particularly great and there's no two-player mode or any real game settings, other than the ability to add a couple of extra colors to the counter set.
Despite all of this, Mastermind remains a great test of your logic that you can play anywhere.