Typically a right-handed pitcher, Greg A. Harris pitched ambidexterously the 9th inning on september 28, 1995 against the Reds. They didn't score as he faced two batters using his right arm and two others with his left. He used a special six-finger glove which was sent to the Hall Of Fame (see picture).
He was the only major leager to toss with each arm in the 20th century. Three ML pitchers recorded that feat in the previous century: Larry Corcoran (1884), Elton Chamberlain (1888) and Tony Mullane (1882 and 1893).