I was over at a friend's house yesterday and we were joking about having a realtime fireplace for the PS3. I imagine you could do one that looked pretty photoreal though, not like this.

More like this:
http://www.youtube.com/watch?v=NYNbDIerysQ

Plus the camera is locked so you could cheat like hell. Also if the controller perturbed the flame, if you could dump on fuel, and change the color, etc. That would rock.