In my mind, it's kind of like "Talk Like A Pirate Day", only it's 1980's themed. It's an excuse to have a good time, one which involves your old DEVO LPs and your copy of The Adventures Of Buckaroo Banzai Across The 8th Dimension and possibly leg warmers if you're into that sort of thing.
It's another excuse to watch music videos from an era when "music videos" were, you know, actually on MTV.
It's a celebration of, and an indulgence in, everything that was cool and silly and weird and awesome about the 1980s.
Never mind the intro, blah blah blah. Skip to 0:50.
But enough explanation, no more justification. Duranmas Duranmas is totally rad. There.
Go forth and party.