
Crytek is registered to demonstrate '3d Development' stuff. They'll be focusing on Cryengine 3, and probably showing off how cool their content creation stuff is. At earlier shows, they showed off their system that allowed them to make a level on a PC and have that content instantly appear on an XBox 360 and a PS3 for testing.
I'm going to guess that they'll be showing off the DirectX11 features they've been working on. Just imagine, actual news about the DX11 patch.
This website has a map of E3 that you can poke around in.