I remember the time I was about 25 years old and was taking a bath. As I sat down in the tub, I noticed that the deeper I got into the water, the higher the water in the tub rose. Suddenly, it hit me! In a flash of inspiration, I realized that the volume of water rising was equal to the volume my body was displacing in the tub!
I jumped out of the tub, ran out of the house, and ran naked through the streets (buck naked), shouting "Eureka, Eureka!".
That was one of the happiest moments of my life.
Some bastard later informed me that Archimedes discovered the same thing a couple of millenia earlier. Oh well, at least I got to run naked through the streets.