Down the line / Down-the-line

Each player should start in the middle of the baseline, 1 person on each side of the court. One person starts the rally by hitting the ball down the line. The other person gets to the ball and hits the ball down the same line. One player should be hitting forehands while the other is hitting backhands. (Assuming both players are either right handed or left handed)
After the player hits the ball they should return to the center of the court and wait for the next down the line shot. It is important not to cheat and stand closer to the side line than you normally would during a match. Putting a cone at the center of the baseline and having the player shuffle thier feet around the cone after each shot will help with this and also work on footwork. Make sure that the players switch after a so many points so that both can practice the forehand and the backhand.