how do you get different game varients on halo 3?

[Shane N]

ill give a list of ones i remember
warm up on warm up
and an other one which is a sand trap variant
and theres a bunch of elephants stacked on top of each other and if you jump on them corectly you can get out of bounce and thats basically the one i really want

so if theres a way to make it or download please tell me

 

[missy1234]

sign up on bungie.net and people may have it on their file share.