Splintercard

Splintercard is a 1 or 2 player science fiction wargame contained in a single 5x7 inch card you can print for free. Most games last less than ten minutes.

Try to destroy your opponent's city. Take turns playing cards which either control your forces, launch nukes, repair your city or skip a turn. There's more to it - the stakes grow as time moves on, there are multiple strategies to win, and a solo mode is included.