Forget about Mars for a second, and let's focus on the moon. This month we already got one blue moon, and we're due for a second on August 31st—which really takes away from the "once in a blue moon" saying (though, fun fact: the next year of double blue moons is coming up in 2018). According to EarthSky, the event on the 31st doesn't mean we'll be seeing a blue-colored moon, only that we'll be seeing the second full moon of a month.
"Every month has a full moon, and, most of the time, the names for full moons coincide with particular months or seasons of the year. By either definition, the name Blue Moon accounts for times when there happen to be more full moons than is convenient. In recent decades, many people have begun using the name Blue Moon to describe the second full moon of a calendar month. The only time one month can have two full moons is when the first full moon happens in the first few days of the month. This happens every 2-3 years, so these sorts of Blue Moons come about that often."
The last time there were two Blue Moons, under this definition, in a calendar year was in 1999. And Space.com's Joe Rao says next (single) Blue Moon after this year's won’t be until July 2015... so, someone plan a party at the moontower or something. We'll bring some sixers.