See the Unreal 4 engine in action in this trailer for Primal Carnage Genesis.
Substance in Unreal Engine 4 Tutorial Series
Allegorithmic have created a tutorial series that covers how to use Substance with Unreal Engine 4.
Unreal Engine - Showcase
This compilation video shows off some of the games built wih Unreal Engine technology.
Houdini Engine for Autodesk Maya
SideFX have released Houdini Engine for Maya, with 3ds Max and Unreal versions coming soon.