A line at the free-throw line.
The 1st 2 players will have a basketball.
The player in front always gets to shoot 1st. As soon as the player in front shoots the player behind can shoot.
If the shot is missed, you get your rebound and can shoot as close as you like. The 1st shot must be taken from the free-throw line.
A player gets knocked out if the player behind scores before they do.
The winner is the last player in the game.
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.
The ball screen produces almost half of all professional offensive possessions, yet most teams still teach it as a memorised play. The modern approach trains the read - giving players a framework to decide based on what the defence does, not what the coach called.