Play baseball rules. Bases are about 35' apart. Pitching distance is about 15'. A basketball, volleyball or sport ball is used. The batter hits it with fist or open hand.
Pitches are underhand.
A base runner is put out by hitting him with the ball. One player tosses a ball straight up and hits it with a bat. The other players try to catch the ball. The batter then lays the bat on the ground broadside to the catcher. The person who caught the ball throws it trying to roll the ball into the bat.