Halo 3 gamerscore?

[Tyler D]

What are all of the tasks you need to do to get 1000 gamerscore points?

 

[Gnomie J]

if you go to your "played games" option and click on halo 3 it will show you the list of what tasks need to be accomplished. Most of them are in multiplayer ranked matches

 

[perfecsaiyan]

Here's the list:

http://www.xbox360achievements.org/achievements.php?gameID=274