And the most interesting mailer goes to Enerjy for displaying US Patent No. 4,320,756 on the front of their mailer. I thought this was pretty damn funny, myself...
Described as a "Fresh Air Breathing Device", this tool was invented by William O. Holmes to enable persons trapped in the upper floors of a burning building to survive toxic smoke by inhaling "clean" air through the water trap of a toilet until they could be rescued.