In the Yankees 1-1 tie with the Reds yesterday, Mo pitched a 1-2-3 4th inning. During the inning, while facing Josh Hamilton, he threw two change ups. First, one to start the at bat and then another one that froze Hamilton for the strikeout. From the New York Daily News:

Rivera turned toward Derek Jeter after the strikeout, flashing a wide grin while holding up two fingers to indicate how many changeups he threw.

"I was laughing the whole time," Jeter said. "Don't tell anyone he's using it."

Yeah, everyone keep it quiet.