Heh...
Catching my ejected round is one of the few "tricks" I have, although I refrain from it when there are shooters at the line. Last thing you need to do is power-swat a live round down to the berm like a Handball. The trick is not hard at all even with the bad arm, easy to practice with snap-caps.
On the other hand, not so much a Trick as a Challenge, I do find myself positioning myself behind my wife in a place to hand-catch her brass as she shoots. Hot stuff, but great for the reflexes, and no bending over to collect it afterward.