It's the equinox, the time of the year that people attempt to balance eggs. And in fact they can. Just like you can during the rest of the year too, but somehow the equinoxes got associated with this.
If you have obnoxious kids, spouses, roommates or others, you might have raw eggs mixed up with hard-boiled eggs. How can you tell them apart nondestructively? You spin them. The hard boiled eggs will be easier to spin because they lack the internal viscous friction and instability of the raw eggs - the yolk doesn't start and stop at the same time the shell does.
If you are the obnoxious one, then get hold of a chalk egg and put it in with the innocents. You used to be able to get them by mail order as a gag - I can't seem to find any just now. In real life they've been placed by hens to "inspire" them. Anyway, it's fun to watch a strong-willed person deal with one.
Then there was the time the rooster saw his first Easter egg. He thought about it for a moment, then went and beat the crap out of the peacock.