Duolingo Dark Version
Turn off your lights and get ready for an new dimension of Duolingo. Instead of having Duolingo light and bright, get it dark. I have it and I recommend it 101%! Just go to this comment: https://www.duolingo.com/comment/1853274 So awesome!
I think everyone who liked it, replied on the original post a year ago. Though you did get one reply yesterday.
If you like this sort of thing, you can also set your background to a flag. Though I should point out that not all flags are supported. See the userscript called Flag Background at: http://duolingo.wikia.com/wiki/Duolingo_Userscripts