Also known as "meteor storms" or "meteor outbursts," meteor showers are basically bits of debris observed falling when a comet swings past the Sun. For anyone who may not already know - a meteor is a small fragment of cosmic debris entering the Earth's atmosphere at extremely high speeds; and a comet is a "dirty snowball" made of ice and rock orbiting the Sun. Every time a comet flies past the Sun some of the ice melts which sheds the debris creating the tail of the comet.
Meteor shower particles travel in parallel paths at the same velocity which makes it look like it comes from a single point among the constellations. It's like being outside on a rainy day and looking straight up through a transparent umbrella.
There are a few types of meteor showers. Leonids, perseids, draconids, orionids, and geminids. The most visible ones are perseids because they peak on August 12 every year with over one meteor per minute falling. The largest are leonids, "The King of Meteor Showers," which happen approximately every 33 years with hundreds of thousands of meteors falling per hour.
Earth is not the only planet to have meteor showers. Mars has them, too. However, those showers are different from the ones we see because of the intersecting orbits. When a comet orbits around Earth it eventually crosses past Mars, especially when it passes the Sun.
The next five meteor showers for the rest of 2007 are listed as follows:
August 12-13 - perseids (about 60 meteors fall per hour; this is fairly consistent every year)
October 8-9 - draconids (there is a peak rate of 10 meters per hour under clear, moonless conditions)
October 21-22 - orionids (peak rate of 20 yellow and green meteors per hour; these move fast at 41.6 miles per second and have been known to produce fireballs)
November 17-18 - leonids (see definition above)
December 13-14 - geminids (this is the most reliable shower of the year; it has a multicolored display (65% white, 26% yellow, and the remaining 9% blue, red and green)
So, keep your eyes and your telescopes pealed, astronomy buffs.