The Argus C3, "The Brick," one of the most popular 35mm cameras in history, selling over 2 million units from 1939 to 1966.
From the wiki:
I have just been displaying this as an art piece along side it's sick old flash attachment and leather case since I found it in a gigantic antique mall in Illinois or Kentucky someplace, but after taking this shot I dug out a roll of 35 and plopped it in there. From what I can tell it still fires well, though the shutter cocking crank is a little finicky so I'm not about to use if for a paying gig or really anything I'm terribly concerned about. That being said, I'll definitely be posting the results of the tests here if any of them pass muster.