This is an Allosaurus Fragilis from the late Jurassic period at the Smithsonian Natural History Museum; - 145 to 155 million years old. Found in Colorado.

Close inspection if it's bird-like feet and recent research means it probably resembled a large Emu or Ostrich, rather than the Hollywood reptile stereotype: modern re-creations of related dinosaurs, like Deinonychus feature a feathered, egg-laying, bird-like creature.

On the other hand, there is a striking resemblance between this Raptor skeleton and the creature in the 1979 horror science fiction movie "Alien."

I call this digital photo, taken in April 2010: