If bored by sudoku, look at this puzzle game.

Hashiwokakero (or Hashi for short) is a Japanese puzzle. Like sudoku, it’s an abstract puzzle requiring reasoning about a number of constraints at once. The numbered circles are islands, your task is to fill in the bridges connecting them. There can be zero, one or two bridges between each pair of islands, orthogonally. Bridges cannot cross, and the number on the island indicates the number of bridges to the island. Lastly, all the islands must be connected.