The rules for Town Ball Game at Ft. Knox (from Mark Rohman, 3rd ME)

The goal is to have people be basically familiar with them (not experts) so
we can have as much fun as possible.
These rules point out the key differences in the 1858 Massachusetts Game and
modern baseball.

O There is no foul territory although certain ground rules may be in
force to ensure the safety of spectators. Anytime the thrown ball touches
the bat the ball is in play.

O A ball caught on the fly is an out as in modern baseball but in town
ball the scout or fielder must remain on his feet after the catch. Diving
catches are not permissible and the ball remains in play if the
scout/fielder fails to stay on his feet.

O The sides change place after one out.

O Runners are not obligated to take a direct course between bases.

O Runners may be put out by "plugging" or "soaking" them with the ball
meaning the ball is thrown at the runners to put them out.

O Tallies (scores) made prior to a catch or plug will be counted.

O When an agreed upon number of tallies is reached the match is
declared for the side first to reach the goal, provided the sides have
batted an equal number of times. Typically the tally goal is set at 21.

O A batter may strike out on three missed swings but only if the
catcher catches the ball on the fly and remains on his feet. For this reason
strikeouts are rare in town ball.

O The thrower or pitcher delivers the ball with an overhanded motion
but at a slow speed and in a manner calculated to assist the striker in
hitting the ball. The thrower was essentially a trigger to put the ball in
play.

Well, that's essentially it. There are other rules such as equipment and the
field of play but those can be gone over at the event. 

Dave B