is there another way to gain exp on halo 3 other than online?

[xXxSDKxXx]

i dont have online and i want to get some of that bad a s s armor so how else can i gain exp??? if not then its ok.

 

[Teno M]

? its ok? your such a duche and you don't even know it, you can't gain up unless your online...thats the whole point of the point system, to play online and to keep Xbox live as the best freaking Online play system ever.