1961 - Jim Gentile of the Baltimore Orioles becomes the first player in baseball history to hit grand slams in consecutive innings

(Wikipedia) - A powerful slugger listed at 6' 4", 215 lb, Gentile languished for eight years in the minors for a Dodgers team that already had All-Star Gil Hodges in first base. Traded to Baltimore, Gentile enjoyed his best season in 1961, hitting a career-highs .302 batting average, 46 home runs, 141 runs batted in, 96 runs, 147 hits, 25 doubles. 96 walks, .346 on base percentage, .646 slugging average and 1,069 OPS. He was considered in the MVP selection (third, behind Mickey Mantle and Roger Maris). In addition, Gentile hit five grand slams -- including two straight in one game --, setting an American League record that stood until Don Mattingly belted six in 1987. Link