Ever seen a blue moon? Well, if you are in "American longitudes", you do not have to wait long: it happens on Thursday May 31 at 9:04 p.m. Eastern Daylight Time (6:04 p.m. Pacific Daylight Time).
However, if you are in Europe, Africa, Asia or Australia, you will have to wait until Saturday June 30 to declare that the moon is "officially" blue.
To find out why, read this article on MSNBC.
-J