There are two teams.
Each side has a flag (If a flag cannot be found a simple nerf football will do).
The object of the game is to capture the opponents flag/ball and bring it back to your side.
Each team is allowed to have no more than 2 guards for the flag.
If, however a player on the opposite team is tagged while on an the enemy's side the player goes to a jail located at the corner of the opponent's team.
The only way to get out of jail is to have a player from your team run to the jail, grab your hand and run back to your side.
But if a enemy tags the 'rescuer' then he/she is in jail also.
There is no guard to jail.
If you are playing with a ball then when you capture it you can throw it back to your side, however if no one on your team catches the ball then it doesn't count.
Thanks to Puja Deverakonda