One of the rarest events in baseball is HITTING TWO GRAND SLAMS IN THE SAME GAME BY THE SAME PLAYER and they are all listed (along with box scores, positional breakdowns, and trivia items) in our fabulous feats section.
On May 26, 1929, New York Giants pinch-hitter Pat Crawford hit a grand slam. Les Bell, from the Boston Braves, pinch-hit and also hit a grand slam. This is the only time in history two pinch-hitters have each hit a grand slam during the same game.
Jim Northrup in 1968, and Larry Parrish in 1982, are the only players in Major League history to hit three grand slams during the same calendar week. However, did you know that Lou Gehrig once hit three grand slams over a four day period in 1931 (August 29, August 31 & September 1)? By comparison it took Northrup six days in 1968 and Parrish seven days in 1982.