One of the representatives from "NASA regional listening post 46A" is identified as Mr Lethbridge-Stewart. Brigadier Lethbridge-Stewart was the head of the United Nations Intelligence Taskforce (UNIT) in "Doctor Who".
The Middleman mentions the "Nakatomi Protocol", and Wendy says "Hans Gruber-ed with our own robot." "Die Hard" takes place in the Nakatomi Plaza building, and Hans Gruber is one of the characters.
The "Yippee-ki-yay" & "Now I know what a TV dinner feels like" lines, along with several others are quoted from the movie. Also the scene in the vents, and the being trapped in a building about to explode all echo the greatest action movie of all time, Die Hard.