Languagehat takes on the naval neologism geedunk. My post to the comment thread:
I had a colleague who was in the Navy in the 1990s; he was stationed, among other places, on Diego Garcia in the Indian Ocean. He taught me “gee-dunk” (pronounced as a spondee) as a word for a break room, a place with a coffee machine, a table or two, and a couple of vending machines. Not at all the ice cream parlor of swankier years. His etymology, or perhaps the etymology that was handed down to him, was that “gee-dunk” was the sound of working the vending machine: the sound of pulling and releasing the knob, and the ka-chunk sound of the sweet and salty treat falling to the bottom tray.