Here is the fake alien video Cutman referred to earlier.
Pretty impressive for something these guys just threw together like this, even though it seems apparent to me that the movement of the creature is highly suspect. It looks like somebody holding a puppet under the window and moving it around like they think it should move... which is exactly what it is, I'm sure, but the point is the motion isn't convincing. Looks like they accomplished the eye blinking with some kind of CG.
The "real" footage from the Denver press conference will be available in a few months. I doubt it will be more convincing than this response hoax, but we'll see.