Here is the second CG episode created for Halo 4's Spartan Ops.
Halo - The Fallen Teaser
A teaser is out for The Fallen, an upcoming Halo fan film.
Halo 4: Forward Unto Dawn - Part 4
The action ramps up in episode 4 of Halo 4: Forward Unto Dawn.
Halo 4 - Concept Art Trailer
There is some inspiring scenery in this concept art trailer for Halo 4 from 343 Industries.