If the batter swings and misses and the catcher catches the pitch, the batter is out. But no play. A ball that touches the ground before reaching the catcher is a free swing. A batter may be retired if the catcher catches a hit in the air or if the catcher holds on to a foul tip. A hit must come to rest at least a bat length in front of the batter, and all hits are singles.
Teams can have any number of players, and every player bats every inning.
But I'm afraid it is a game of past generations. You always can find a game at the beach, but I haven't seen a pickup game in a park or alley in years. Perhaps it's the regimented world of little league baseball that steers kids away early. Or maybe i just don't know where the action is and the game is as healthy as ever. I hope so.