I was reading about old board games recently, and came across one called Hex, also marketed at one point as Con-Tac-Tix, and it looked pretty cool.  Seemingly, it's out of production, and has been for a long time, but thanks to 3D printing we can bring it back to life!

The rules are simple - two players take turns placing pieces on a hex board, and the goal is to make a continuous line from one side of the board to the other.  Things get strategic very quickly, but it's mathematically proven (by John Nash, the guy played by Russell Crowe in A Beautiful Mind, no less) that the game will always have a winner, and won't ever end in a draw.   More history and insight can be found on the Wikipedia page for the game:

Wikipedia: Hex_(board_game)

So, some notes about this design!

* You'll need enough pieces for each side.  Now, there's probably a mathematically-derivable maximum number of pieces that might ever be used in a realistic game, but I just printed 61 pieces for each side, which is enough to completely cover the 11*11 board.
* The board is split into four pieces, so that they can be printed on a conventional printer, and for easier storage.  
* The board pieces have insets for adding magnets, should you want to get fancy.
There's also a box design, which is visible in some of the photos, for stylish storage!  You'll find that here:

Custom Box: Hex Game Box

Hex is a cool game - hope you enjoy it as much as I am!