The NYTimes has an article on the 10 most beautiful experiments of all time.

...Most of the experiments -- which are listed in this month's Physics World -- took place on tabletops and none required more computational power than that of a slide rule or calculator.

What they have in common is that they epitomize the elusive quality scientists call beauty. This is beauty in the classical sense: the logical simplicity of the apparatus, like the logical simplicity of the analysis, seems as inevitable and pure as the lines of a Greek monument. Confusion and ambiguity are momentarily swept aside, and something new about nature becomes clear. [New York Times]

I even remembered some of these from science classes back in High School.