I called a 10-second free-throw violation during my second year. Front end of a one-and-one, no less. In a close game. Let's just say my partner provided some forward-leaning mentorship afterwards. I have never called it since. One time I counted (slowly) to 15. Still didn't blow it.
How about this for rare. Don't have my book in front of me, but a live ball (not a try) that enters the basket from behind the three-point line. Counts as two points. Never thought I'd see it, and then sure enough a Duke player a couple of seasons ago trying to save a ball from going out of bounds in the corner flipped one right through his opponent's basket. Damn the bad luck. The crew was right on top of it and made sure the score was a 2 and not a 3. No one in the entire place knew that rule except the officials.