Prediction: Pain - 2500 XP
Complete any Campaign Mission on Heroic or higher difficulty with the Famine, Luck and Thunderstorm skulls.

Infinity and Beyond - 6117 XP
Complete Infinity on Legendary difficulty with the Mythic, Tilt, Tough Luck and Thunderstorm skulls.

Spartan Ops

Shield Break! - 1500 XP
Kill 70 Jackals.

I am the 99 Percent - 3500 XP
Kill 80 Elites.

Destroyer of Grunts - 1100 XP
Kill 100 Grunts.

War Games

That's Just Perfect - 6950 XP
Complete a War Games match with at least 15 kills without dying.

Dominator - 4750 XP
Win 40 matchmaking Dominion matches.

Click here to see a complete list of this week's Weekly Challenges.
Hi bs angel,

Regarding the "That's Just Perfect" challenge, I just completed an Oddball game with 15 kills 0 deaths, yet the weekly still says 0/3 and my Perfection commendation hasn't increased. What gives?

It does say complete a War Games match, not a Slayer match like how it was in previous Halo games.