In this game, the game is divided into innings. You can have as many innings as you wish, but 3 is a good place to start. You can always add more innings later if things get interesting.
Each inning is made up of one team batting, and one team fielding, then the roles are switched. The players go through their rotation so that the same pitcher and batter always throw against one another until the batter is either out, or gets on a base.
The pitcher goes first and attempts to get a bullseye. The batter throws second, and tries to outscore the pitcher. This can go one of three ways:
The pitcher ends up with the high score = The batter is out. The pitcher and the batter rotate out and the next two pitchers step up to throw.
The batter gets the high score = The batter advances the number of equal to the difference between the scores. Bullseyes always count as 5. This will also allow runners already on base to move the same amount of bases.
The batter and the pitcher tie = This results in a strike, both players throw again. If it happens three times in a row then the batter will be considered out, and the next two throwers step up to throw.