In the classic Battleship, you arrange your naval war ships in a grid and try to take out your opponent's ships before they take out yours. When your ship is full of red plastic you make a hideous bombing noise and say, "You sunk my battleship."
Wikipedia's history of the game is actually interesting. Excerpt:
In The Dillinger Days, historian John Toland writes that prisoners in solitary confinement in the Indiana State Penitentiary played a version of Battleship during the 1920s, marking squares on their cell floors and calling out attacks from cell to cell. "For years the more obtuse guards wondered what was being plotted when they heard men calling: 'B-7.' 'Miss.' 'C-8.' 'Destroyer sunk!'"If you have the unexplained desire to play too and can't challege or um, bribe someone into playing a game with you, you can always use the not as fun computer version.