In the 1992 U.S. Presidential election, all three major candidates were left-handed. (George H.W. Bush, Bill Clinton, and Ross Perot)
Polo must be played right-handed. Left-handed play was ruled out in 1975 for safety reasons.
Using a standard "qwerty" keyboard, and typing with both hands in the conventional manner, the number of words in English that are typed solely with the left hand is in the neighborhood of 3400. Around 450 words are typed solely with the right hand.
1 in 4 Apollo astronauts was left-handed, a higher percentage than the general population.
The Scottish Clan Kerr is often associated with a high incidence of left-handedness. Their Ferniehirst Castle, built in the 15th century, is said to have had staircases that spiraled to the left instead of the right.1