Here’s a game idea that primarily uses a standard deck of cards & a board. Loosely described, because I’m not out to write the rule book in a blog post, but I think you’ll get the idea.

Divide a deck into two halves - each half as a complete red & black suit. These halves form each player’s personal decks.

On the board, each player has a certain number of ‘card stacks’ - a combination of red & black cards that are face up such that only the top card is visible. Red cards are attack cards, black cards are defense cards. At no point can a player rummage through his opponent’s card stacks to see what cards are there.

Every round, players draw some number of cards from their deck. They then place those cards face up on any stack that they choose. If they have less than 5 stacks, they can place a card on an empty space to form a new stack.

Once players have placed all their cards, they start taking turns activating stacks. A stack can only be activated once per round. When a stack is activated, it can perform 2 actions out of the following list:
* Move - move a single space
* Attack - attack an adjacent opponent card stack
* Combine - place the stack on top of an adjacent stack, forming a larger new stack
* Divide - take any number of cards from the stack and form a new stack in an adjacent space

Those are mostly self-explanatory except for attacking: when a player chooses to attack another stack, both players reveal the cards in their stacks. The person with the most attack (red) cards is the winner. For each attack card in excess, the loser must give the winner a defense card. If the loser has no defense cards to give, he must give the winner all the attack cards. In the event of a tie, nothing happens.

The cards provide victory points equal to the face value of the card. The winner is the person with the most victory points at the end of the game. ‘End of the game’ conditions have yet to be determined - either once a player hits a certain number of victory points or a fixed number of rounds I think.

That’s basically it. Exact numbers for things (board size, max # of stacks, victory points to win, # of actions per turn) are subject to iteration and actual playtesting. There’s also room for special rules like making face cards do something special when in a deck. I see this as a potential mobile asynchronous multiplayer game as well, but it’s worth roughing out a prototype to try it out.