If you're sick of Sudoku then have you tried Sokoban? Ben Ruyl Sokoban is a resissue of the classic Japanese game Sokoban with more than 500 levels. The object of the game is to place all of the boxes in their correct position in a crowded warehouse with a minimal number of pushes and moves.
The boxes can only be pushed, never pulled, and only one can be pushed at a time. It sounds easy, but the levels range from very easy to extremely difficult, some taking hours and even days to figure out. It is the simplicity and elegance of the rules have made Sokoban one of the most popular logic games in Japan and you'll soon see why.
If Sudoku and numbers are not your thing, then you'll find Sokoban both stimulating and relaxing.