The third episode has been released for Halo 4: Forward Unto Dawn.
Halo: Nightfall - Official Trailer
The official trailer is out for the Halo: Nightfall series.
Halo - The Fallen Teaser
A teaser is out for The Fallen, an upcoming Halo fan film.
Halo 4 Spartan Ops - Episode 2
Here is the second CG episode created for Halo 4's Spartan Ops.