94-year-old Harry Tomlinson was amazed when his apple tree began to grow plums and blackberries, as well as apples. The 'fruit salad' tree generated some media interest, but horticulturalists took one look at the tree and saw that the plums and blackberries had simply been pasted on. The identity of the hoaxer remains unknown (assuming that it wasn't Mr. Tomlinson himself).
Update: Here's an article about the 'fruit salad' tree before it was debunked. I like the explanation that one horticulturalist attempted to provide to explain the fruity anomaly: "One explanation is the tree may have developed some kind of fungal condition which can produce what are known as pocket plums which are actually apples. As for blackberries, I am sorry but it shouldn't happen."