Floor!
Certainly one of the most interesting things about poker is the amount of random situations that arise in which it is necessary to go deep into the rule book to figure out how to proceed. At least once a day, sometimes once a level, we hear a dealer cry, "Floooorrrr!"
Just now, we heard a floor call for Table 19. From what we can gather, Player A and Player B were heads up and reached a river showdown for a pot worth around 1,500 chips. Player A told Player B that he had ace-high to which Player B responded, "That's good." Player A then threw his cards to the dealer face down, expecting to be shipped the pot. However, he never showed his cards and Player B still had his. The rule is that the winning hand must be shown at a showdown and Player A could no longer do that.
The first floor man that was called over was unsure of what to do so a second floor man was called over. He ruled that since the cards had not yet hit the muck (one was in the rack while the other was sitting next to a random players chips), the hand was not dead. He also ruled that the dealer was not allowed to table a hand. Player A looked confused for a second before taking the hint, reached across the table and flipped over his cards. Player B mucked his hand and the pot was shipped to ace-high.