I don't know if this has been posted before, but there is an awesome livestream webcam showing the ramp (between Piers B and C I guess?) at DUS. If you have DSL or other high-speed internet it should be quite smooth while playing.
Other webcams show the departures lobby, a view of the runways (not that great though) and the landside arrivals and departures roadway and monorail. Pretty cool!