On March 31, look at the sky. You'll see a sight that no one has seen since 1961--the second "blue moon" in a year. No, the moon won't look blue (though it can when there's a haze of volcanic ash). A blue moon is the second full moon in a month.
There was a blue moon in January. The next double-blue-moon year will be 2018. By then, folks might live on the moon!