Captain's checkers is a variation on the classic board game checkers (or draughts, whichever name you prefer). It was invented by myself years ago and has been introduced to several of my friends; it has seen years of play and honing of the simple rules. I have been told that it is similar to the Milton Bradley board game Domination, now out of print, but I have no knowledge of or information about the other game. Essentially, captain's checkers takes the pieces of checkers and creates a very subtle strategy game that seems to be nearly impossible to truly master.
Captain's checkers requires that you have three checker sets with compatible and stackable checkers, since most sets only provide 12 to a side; each color needs thirty two pieces to start with. You only need one of the boards, however.
Starting the game is quite simple. Use a standard 8x8 checkerboard and fill the two home rows on each side with double-stacked checkers, meaning stacks of two checkers of the same color, much like kings in the regular checkers game. In the end, each side will start with their two home rows filled with 32 checkers of their own color, each stacked two high.
Playing the game is similarly simple. If you have a stack of checkers of height two, the stack can move exactly two spaces in a straight line (horizontal, vertical, or diagonal) in any direction; if it lands on a space with checkers already on it, stack the ones just moved on top of the others there. This constitutes a single turn, and the players alternate turns moving only the stacks they control.
The control of this newly-formed taller stack is possessed by whichever player is represented by the color that is topping the stack and, for purposes of keeping track of who is winning or losing, is considered to be the owner of all of the checkers underneath the stack. The stack can move as a regular piece, just moving an equal number of spaces to the height. If the move would move the piece off the edge of the board, it is illegal and cannot be made.
The real subtlety of this game comes with the stack splitting rule: instead of moving a stack, you can instead divide the stack into two equal pieces, moving the part on top to any horizontally or vertically adjacent square (yes, this can be onto the top of another stack!). You can execute this split however you desire, but each stack must have at least one checker. This splitting constitutes a turn as well.
It is next to impossible to actually have one person control all of the checkers, unless one person is extremely experienced with the game and the other is just starting. Thus, the rule of thumb for victory (which may be adjusted at the agreement of both players before the game) is that if at any time one player controls 75% of the checkers on the board, that player is immediately declared the winner. This avoids some nasty deadlocks and the necessity for long, drawn out pinning combinations for a single checker.
The game can be played in as little as fifteen minutes; other games have sat on a table for days as both players study the pieces. It might be a good idea to put limits on turn lengths, because some turns will require a great deal of thought by one player and can cause the game to drag on for a long time.
Over the years, there has been something of an "opening theory" developed about this game, much like there is in go and in chess. Much of the excitement of this game revolves around the opening moves and clever setup of pieces for the capture-heavy turns to come.
This game is my abstract strategy game of choice, which is saying a lot considering my shelves are lined with Twixt, chess, checkers, shogi, and go. The pieces are readily available, the rules are extremely simple, and the strategy is extremely subtle; in all, it's a great way to spend a mentally stimulating rainy afternoon.