On Sept 6, 2011, ANA Airlines had one of their flights flipped almost 180 degrees, because one of the pilots pressed the wrong button. The weird thing is that although passengers felt the turbulence, they didn't know they had flipped almost upside down, I guess because of the same forces that confused these pilots. It's a scary thing, and if I remember correctly, its the same thing that killed JFK Jr.

http://blogs.wsj.com/japanrealtime/2011/09/29/wrong-button-s...