That's neat. A group of physicits, coordenated by Robert P. Crease, a member of the philosophy department at the State University of New York at Stony Brook and the historian at Brookhaven National Laboratory, was invited to chose the the most beautiful experiment of all time. The result was publish in a pape by George Johnson in The New York Times and that's the result of Science's 10 most beautiful experiments:

1. Double-slit electron diffraction
2. Galileo's experiment on falling objects
3. Millikan's oil-drop experiment
4. Newton's decomposition of sunlight with a prism
5. Young's light-interference experiment
6. Cavendish's torsion-bar experiment
7. Eratosthenes' measurement of the Earth's circumference
8. Galileo's experiments with rolling balls down inclined planes
9. Rutherford's discovery of the nucleus
10. Foucault's pendulum

The site contains short explanations of the physical experiments with computer animations. More amusing scientific experiments at List of famous experiments and Timeline of Fundamental Physics Discoveries. (via del.icio.us)