Evolutionary biologist, PZ Myers, filmed the development of a zebrafish embryo. He used time-lapse photography, reducing 18 hours of cell division and differentiation into less than a minute of vision. You can read more about the process and a whole bunch of other entertaining and thought-provoking stuff at Pharyngula.
If you haven't had your fill of the amazing biological process that turns something as simple as this into a complex organism, then check out David Nelson's photographic log of frog development. It's updated regularly.
