How to Play
The basic rules are pretty simple. Print out some cards and cross out a square when the play occurs with either team batting. However, to explain my design decisions and settle any arguments that might arise, here are some special rules about various plays:
I have split up singles based on where the ball is hit. Since baseball bingo is designed to require no judgment calls from the player, the hit location is defined by which fielder fields the hit. For the three outfield single squares (left, center, right), this player will be an outfielder. The infield single square means any other base hit, most likely a bunt or a grounder that an infielder could not play cleanly. Infield singles also include hits fielded by the pitcher or catcher. This design spreads the probability of getting to check off a bingo square. If singles were not split, the base hit square would almost always occur early in the game. However, getting a bingo would take longer because fewer squares would have a probability as high as the (split) singles.
Also to even out probabilities, I have grouped together balks, passed balls, and pick offs. Any of these events should mark off the square.
Unassisted plays apply to any out made by only one fielder regardless of how the out was recorded. This includes foul pop outs.
Sacrifice flies and sacrifice bunts override the play for an out that follows. For example, a sacrifice fly to center allows players to mark off the sacrifice fly square, but not the fly out to center square.
The called or swinging aspect of a strike out applies only to the final strike.
Wild pitches and passed balls count only when the official scorer scores them as such. This essentially means that wild pitches and passed balls can be marked off only if a base runner advances because of it.
Ground-rule doubles are counted as doubles.
If the game seems to play too quickly and finish sooner than you would like, consider only marking off plays that occur for one team or the other. For a variant somewhere in between in terms of time, use an entire sheet of paper (2 connected cards) and play one as home and the other as away. Consider it a win if either card gets a bingo.