March 18: the crescent moon will be clustered with Jupiter, Mars, and Saturn
March 19: Jupiter, Mars, and Saturn will still be clustered together
Also March 19: it's the first day of spring and the sun will rise due east and set due west
March 20: Mars slides below Jupiter
And when all of these things happen in just a couple of days ... it's a conjunction conjunction.

Got the song stuck in your head now? You can share Schoolhouse Rock's Conjunction Junction with people who have never heard it here.