My favorite example of this is Archimedes. When someone touts the virtues of being at your desk without turning your head away from the monitor and lifting your hands off the keyboard I usually ask "where was Archimedes when he had his "Eureka!" moment?".
To be fair, the story actually shows me was doing something related to his study when he made his discovery. In a bathtub that was too full, he found that physical objects cause water displacement. He wasn't planning on making a breakthrough, but it didn't just come to him out of the blue.
