A interesting story that took a 2 and a half hour physics lecture to learn:
Apparently, around the time Max Planck was in school, everyone was having a big problem explaining Black Body Radiation. You see, the graphs that were produced by observing star's temperature's could not be reproduced using Newtonian physics
Planck apparently spent quite awhile working on the theory of quantized energy. Eventually, he was able to come up with a theoretical formula that exactly reproduced experimental measurements of Intensity of light against density against temperature.
Unfortunately for Planck, this formula required the use of a constant, which all energy had to be a integer multiple of. Whether my physics professor exaggerated here is for someone else to say, but Planck was apparently laughed out of school and of physics circles for these herectical notions.
A few years later, this guy Einstein comes along and explains the photoelectric effect, except that to explain why only short wavelength light could force an electron to jump off a metal plate, he had to introduce a constant.
This constant was the same one that a few year's earlier, Planck had tried to explain Black Body Radiation with. Planck was then let back into physics circles, proclaimed as a hero and a visionary, and eventually they gave him one of those nifty Nobel Prizes.