I was told once in a class that the whole story of Newton and the apple was a myth invented many years later, but some quick Googling found this memoir by William Stukeley, a friend and biographer of Newton, who recounts the story. The apple didn't hit him on the head, as sometimes shown in cartoons, but Newton was walking in the garden thinking about why apples always fall straight down, rather than at some angle, and he came up with his first formulation of the law of gravity. Here is Chris Maddison's LEGO rendition.