Halo's very own "Nazi Zombies" & "Hordes" its called...

...FireFight!

Halo 3: ODST's Fire Fight is its own variation of endless waves of enemies.

Basically, you and 3 other friends have to hold off endless waves of Covenant lackeys and leaders.

See more "hurr" :http://www.youtube.com/watch?v=Z4IVyFhxySM

("Hurr" is an Inside joke)