Accidental or Serependitous discoveries

There have been many accidental discoveries.
For example, the drug penicillin was discovered by a slob who didn't clean up after himself. Biologist and pharmacologist Alexander Fleming neglected to wash his staphylococci bacteria culture before he went away on vacation. When Fleming returned a few weeks later, he observed mold on the plate that the bacteria would not grow around. This fortuitous discovery eventually led to the development of the wonder drug penicillin.
Physicist Wilhelm Conrad R�ntgen wasn't out to revolutionize the medical field, but that's exactly what he did when he discovered X-rays. The curious R�ntgen wished to see if cathode rays could escape "a glass tube covered in black cardboard." R�ntgen eventually discovered these rays could be used to photograph the human skeleton, and, like Fleming, he won a Nobel Prize for his efforts.