Mass combat is a special case that is often handled differently from the normal combat rules in many roleplaying games. If you tried to run a fight involving a hundred or more combatants using the detailed one-on-one hand-to-hand rules designed for small encounters, you could be rolling dice until the cows come home. What you need is a way to give the players something to do while not requiring a bazillion dice rolls to figure out how many of the vast cast of supporting extras are being incapacitated in the background.

Since mass combats don't actually happen that often, the change of rules can be a little disorienting. At times like these you need a rules expert on hand.

This goes for both the GM and the players.

Transcript

Mace Windu: I jump into the arena.
GM: The droid army marches in and starts firing. The Jedi fight back.
[SFX]: Pow!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
[SFX]: Whooom!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
GM: Anakin, Obi-Wan: Two Jedi toss you new laser swords.
[SFX]: Whooom!
[SFX]: Pow!
Mace Windu: Fight! Fight!
Obi-Wan: The climactic battle! I almost hate to say this, but it's a shame Pete isn't here for this.
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
[SFX]: Whooom!
Mace Windu: Fight! Fight!
Anakin: No it's not.
Mace Windu: Fight! Fight!
[SFX]: Pow!
Padmé: He knows the mass combat rules inside out. If anyone can get us out of this, it's Pete.
[SFX]: Whooom!
Mace Windu: Fight! Fight!
Anakin: Pete got us into this.
Mace Windu: Fight! Fight!
Padmé: Exactly! Who better to get us out?
[SFX]: Whooom!
Mace Windu: Fight! Fight!
[SFX]: Whooom!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
[SFX]: Pow!
[SFX]: Pow!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
Mace Windu: Fight! Fight!
GM: Okay Sally, roll to hit.
[SFX]: Whooom!
Mace Windu: 5!
GM: You miss.
Mace Windu: Aww.