Someone once mentioned to me that it's impossible to throw a tennis racquet (or similarly shaped object) into the air, perpendicularly to the string plane, in such a way that it won't turn.
What is this effect, or was he talking rubbish?
I'm sure you've also observed this effect when throwing a spatula, frying pan, or remote control.
In terms of rotational inertia, the "easiest" axis of rotation for the racquet is straight through the handle. The "hardest" axis of rotation would be straight down (perpendicular to the strings).
But when there's rotation along the "intermediate" axis (the one you describe), the other axes (especially the "easiest") become extremely sensitive to random perturbations.
See this thread on math overflow. (And the nice videos in the question and the answers.)