Another brilliant tennis activity idea from John Carrizosa and yes, it is another in a long line of
One player is tasked with hitting fed balls. A second player is behind them a safe distance away, no racquet. Front player hits as many balls as possible to keep rear player from collecting any balls. After a certain amount of balls are fed, players switch positions. Player collecting most balls from rear position wins.
John's video features only two players playing this game. I envision this also working with multiple players in the rear chasing balls if you can keep the chaos to a manageable level. I tweaked by allowing rear player to collect any ball that did not make it over the net.