I think SSBB used it, if I remember correctly (random thread on Fun Motion's forum).
Badspot, PORT IT INTO BLOCKLAND :D
Age of Empires III used it. Also, I don't think anyone here would even know how to use it, so I don't think it's not that big of a deal. It's not like you can just plug it into your game and say "Tada, physics!"
Let's see how this runs on my torque based game.
havok is a physics engine, you still need a game engine to do anything with it.Oblivion used it, Source uses some form of parts of it, I don't remember what else used it really. Apparently motorstorm did.Either way I don't see how this affects most of you.