Interestingly enough, at how two people have written a write up about this, and that you actually sat down and read it. I was able pull this off nicely in Jedi Knight: Jedi Academy.
In the very last level, if you chose the light path, there will be Jedi to help you along through the level fighting the Sith. One of the most useful powers in the game, and one that every NPC is proficient in is Force Push. Anyone who has played the game knows that all weapons, except for the lightsaber and high explosives that you do not fire directly at the opponent, are completely useless against Sith, because they either use their saber to deflect, or push the round back at you.
Now to get the tennis match going you need a Jedi, a Sith, (both of which aren’t fighting anyone.) and a rocket launcher, grenade launcher, or simply a grenade. Find out where the Sith, is hiding using Force Sight, then get a line of sight with them, and fire a volley. The Sith will deflect/push it back at you, and your Jedi buddy will then deflect push it back at him. Since the rockets and grenades only detonate on impact, this will continue until one of them finally runs out of force points.
The fun part is if you have several Jedi with you. The tennis will continue back and forth because Force Push doesn’t accumulate, but if you throw in more rounds the Sith will have to Force Push more often, and each Jedi will only have to concentrate on one object at a time.
I have been able to get six rockets bouncing back and forth in the air for about ten seconds before they all collided on the Sith.