This is most likely the most bizarre concept you'll come across today. Danish indie game 1916 - Der Unbekannte Krieg (The Unknown War for those who were not invaded during WWII) is an award winning project released last spring by a small team at the Danish Academy of Digital Interactive Entertainment. Yes, that one.
Apparently David Adler, the game's director, "envisioned the juxtaposition of two universes that seemed equally unreal to him: the horrors of World War I and the brutality of the age of dinosaurs." And who can argue with that? Macbody Games has picked up the project for a console release, so more people will get a chance to play it sometime down the line.
You can play the browser version of the game right now, which is pretty tense. There's just something about traversing trenches while a raptor can lurk behind any corner. Give it a try!