If you've ever used the expression "once in a blue moon" to describe something that doesn't happen very often, you can test out that proposition this evening. We North Americans get to experience the proverbial celestial event tonight, so all kinds of long sought after behaviors might transpire.
The technical explanation of what a "blue moon" is has nothing to do with the satellite's coloration. It's merely a second full moon in a calendar month. It may not be a frequent event, but it's also not rare on the scale of a Cubs World Series victory (99 years and counting). We get to experience them once every 32 months, on average.
If you've got an unfamiliar place you've been planning to go, or an exotic cuisine you've been hankering to try, or a partner-requested chore you've promised but not yet delivered on, tonight is a good night to take care of it.
Yahoo! News has more details on the phrase and its origins: The Truth Behind This Month's Blue Moon