Fantasy is not the sort of thing that most companies would think of first when they wanted to motivate and engage employees. It sounds a little too un-worky.
If I have learned anything over the years though, fantasy is essential if you want people to break out of standard ways of thinking. Fantasy is a safe place for peoples minds to dream, create and explore ideas. It is a place where they can make mistakes without fear of punishments, where they can be someone else who is potentially braver or totally different from themselves. Great innovations can come from daydreams, imagine the power you could harness by facilitating this mentality!