I know how to use the Custom Challenges and all of that. I wanted to know if anyone has a way to use them to hit the credit cap everyday or to use them to get a lot of credits everyday. Thanks
i use them sometimes to hit credit cap 
> i use them sometimes to hit credit cap 
Lol I know you can but do you know the best way to use them? Like campaign kills or matchmaking.
Campaign -ONI: Sword Base
Kills of enemy & Medals
http://forums.halo.xbox.com/yaf_postst46407_Custom-Challenges-25K-Every-6-Min.aspx
I use it to my advantage in SWAT. If you can find your average kill an hour and keep a steady playtime of 4-5hrs you can determine your challenge that way. My kill per hour is roughly 100 so i put in 450 headshots for 5hrs of gameplay and end up with 30k cr at the end of the gameplay. I also put in about 500 kills because they count headshots as kills too so you can knock down 2 birds with one stone. This will give you between 15k -20k cr. Remember tho, you have to be decent in swat and be able to play 4-5 hours at a time doing this. I hope this helps