Sudoku on PSP. It's not actualy that bad an idea. It works pretty well too.
For anyone who doesn't know, Sudoku is a number puzzle. Nine large squares each with nine small squares in those. Each small square is for a number between 1 & 9. Each line across or down plus each square should contain the numbers 1 - 9 with none missing & none duplicated. This is essentially a type of logic problem & has grown in popularity a great deal recently featuring in newspapers & magazines.
The PSP game features thousands of these number puzzles. They vary in difficulty from easy to hard and can be played as many times as you like. To be fair you could play this forever because by the time you've finished, you'll have forgotten the answers & be able to start all over again.
If you like sudoku or you like puzzles you might well enjoy this game. It is fun, you can download more sudoku puzzles online for free. Plus you can send a puzzle to your friends to play with game sharing. It's very good. As long as you like puzzles.