I got a Palm Treo recently, and my girlfriend immediately loaded it with 52344897 little puzzle games, some of which are good, some of which are not. One of the ones I enjoyed was "100 boxes".
If you've never seen it, the premise is very simple:
-given an empty 10x10 grid
-you must touch every square on the grid once, and only once.
-you can start anywhere.
-after the first move, you may only touch squares that are either 3 away horizontally/vertically, or 2 away diagonally.
Here's a little animated .gif:
I'm curious how many different solutions people can come up with. I've solved by taking 2 different approaches to a similar overall strategy. (I don't want to say more, as I don't want to give any hints) I also don't want to spend any more time searching for other solutions, so I offer it to the board.
Ok, 1 hint: the starting 3 moves shown in the animation are NOT how I did it. I'm not sure if that is a valid start or not.