...what do you think should be in it?
Forge of course (but any additions?) like setting areas on walls where you can set a different point of gravity so you can walk on walls. Or setting up AI in the game (elite, grunt, marine, spartan, etc) that have certain jobs (like capture a flag) and/or abilities (like jet pack or super duper ultra jump).
What about changing options in campaign like bottomless clip or invincibility just to have fun.
Your spartan or elite
Maybe there could be an option to change certain parts of your armor (single shoulder piece or single foot) to be more unique. Creating your own armor pieces would be cool as well.
Post something below on what you think
[Edited on 02.01.2011 6:01 PM PST]