Left Handed Whoppers
In 1998, Burger King ran an ad in USA Today, saying that people could get a Whopper for left-handed people whose condiments were designed to drip out of the right side. Not only did customers order the new burgers, but some specifically requested the "old", right-handed burger.
Apple buys the Beatles
Bob Lefsetz released an April Fools' Day letter which had rumours circulating around the music industry, which in 2010 turned out to be true.
Aussie claimed to have towed an iceberg
In 1983, Australian millionaire businessman Dick Smith claimed to have towed an iceberg from Antarctica to Sydney Harbour. He used a barge covered with white plastic and fire extinguisher foam to convince witnesses.
Taco Liberty Bell
In 1996, Taco Bell took out a full-page advertisement in The New York Times announcing that they had purchased the Liberty Bell to "reduce the country's debt" and renamed it the "Taco Liberty Bell". When asked about the sale, White House press secretary Mike McCurry replied tongue-in-cheek that the Lincoln Memorial had also been sold and would henceforth be known as the Lincoln Mercury Memorial.