Floorboard Music

Music that one keeps under the floorboards or otherwise hides because
a) it's so good you have to have it nearby to listen too and
b) you can't risk someone finding out you like this stuff.

If you to look cool and alternative put some black metal and Avant-Garde Jazz albums on prominent display. It's OK to like Mileu Cyrus or Justin Beiber but they're more like floorboard music.