Scramble the picture, and then spend hours trying to get it back to exactly how it was before you were foolish enough to scramble it.

When the picture loads (in that blank space below), click the 'Start' button to scramble the pieces. To fix it, click a square to move (it will be outlined), and then click a destination square, and the two pieces will swap - you'll see what I mean.
If you give up, or just want to see what it is you're trying to piece together, click the 'Reset' button.
If any part of picture greys out, just click anywhere inside it, and it will miraculously reappear.