Here's a clip from The Amazing Spider-Man 2, and a featurette about scoring the film.
Making A Digital Spidey for The Amazing Spider-Man 2
Sony Pictures Imageworks has released a video detailing the creation of a CG Spidey for The Amazing Spider-Man 2.
Guardians of the Galaxy - Four Clips + Viral Video
Marvel have released four clips and a viral video for Guardians of the Galaxy.
Captain America: The Winter Soldiers - Making of VFX
fxguide go behind the scenes on the major VFX sequences of Captain America: The Winter Soldiers.