I've read you actually can make an egg balance upright on its own. There's a myth going around saying this balancing act is possible only on the vernal or autumnal equinox, the first days of Fall and Spring, approx. Sept. 21 and Mar. 21. I have read that the equinox part is just a myth, and the egg can, in fact, balance anytime of the year. (I haven't tested this, and don't know if it's true)
According to experts, on the Spring Equinox and Autumn Equinox, the day and night are of equal time both in the southern and northern hemispheres. The earth's axis, on its 66.5 degree tilt, is in a relative balance of power with the earth's orbit around the sun. Thus it is a very conducive time for standing eggs on end.
Have you ever balanced an egg on it's end or seen it done? No well now you have! March 20th is the first day of spring, or "vernal equinox" as astronomers call it vernal meaning "of or pertaining to spring," equinox meaning "equal night." As the earth's angle is toward the sun changes throughout the year, lengthening or shortening the days according to season and hemisphere, there are two times through out the year when day and night are of more or less equal length the spring and autumn