Question: When was the last perfect game thrown in baseball?
Answer: August 15, 2012
Disambiguated questions and answers: question: When was the last perfect game thrown in baseball by a RHP?
When was the last perfect game thrown in baseball by a LHP?
answer: August 15, 2012
May 9, 2010
Natural Questions answer: August 15 , 2012 (from the Wikipedia article "List of Major League Baseball perfect games")