extra innings

If a baseball game completes 9 innings with a tie score, then at least one more inning must be played. Each team gets 3 more outs. If there is still a tie, another inning is played.

The longest extra inning game in Major League Baseball history was in 1984 when the Chicago White Sox and the Milwaukee Brewers played 25 innings. It took 8 hours and a few odd minutes. Chicago won, 7 to 6. This was also the longest game on record.

There was a game in 1920 between Brooklyn and Boston which lasted 26 innings prior to being called as a 1-1 tie on account of darkness. There's no record of how long that game lasted, but I bet lots of soap was required in the locker room afterwards.