"This is the plan. Get your ass to Mars, and go to the Hilton Hotel and flash the fake Brubaker I.D. at the front desk, that's all there is to it. Just do as I tell you." -Total Recall
Every two years, Earth passes Mars in orbit, as the inner, faster world overtakes the outer one. This year, it happens when Earth approaches aphelion, its farthest point from the Sun, while Mars approaches perihelion, or its closest approach.
On May 30th, the two worlds pass within just 0.51 A.U. (76 million km) of one another, their closest encounter since 2005. While Mars will still appear as no more than a point to unaided human vision, telescopes will provide absolutely spectacular views during the next three months. If you miss it, you'll have to wait two years for views this good, and then you won’t get them again until 2035.
Woohoo! Time for the 'Mars bigger than the Full Moon' hoax email to make the rounds again.
". . . across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us. And early in the twentieth century came the great disillusionment."
H. G. Wells
Alas, Mars will be at quite a southerly location in the sky, at Declination -21 degrees or so. Those of us in the northern hemisphere will have to look through quite a bit of the Earth's atmosphere to see Mars during its opposition. The view from the southern hemisphere will be much better.