One night in 1921, the physiologist Otto Loewi suddenly awoke at 3:00 am, having dreamt up a brilliant experiment promising to shed light upon his studies of the chemistry governing the action of human nerves. Loewi jotted down a quick note and went back to sleep. Upon waking in the morning, however, he found himself quite unable to read his own handwriting (the typical comedian's dilemma).
Fortunately, the following night he had the same dream and awoke again at 3:00 am. This time, he jumped out of bed and went straight to his laboratory to begin his work. Just two hours later, he had made a novel discovery, as a consequence of which he was awarded the Nobel Prize for Medicine in 1936.