Tonight will mark the peak of the Geminid Meteor shower for 2015, thus marking the climax for the 2-week event. Every December, Earth passes through the stretch of space junk shed by the mysterious 3200 Phaeton (thought to be a spent comet now resembling an asteroid because all of its ice has melted), reaching the deepest concentration of debris tonight. According to some estimates, under ideal conditions (dark country skies), one can expect to see 100 meteors per hour. The reason the meteors are called Geminids is because the meteors seem to radiate from the constellation Gemini. The best time to view the shower is in the predawn, as Gemini is at its highest then.
Don't want to stay up that late? Don't worry, Gemini is clears the horizon around the time the sky gets truly dark, making this an all-night event. However, unless one lives out in the country, the early night hours will probably involve Gemini being low in a light dome. To improve odds of seeing meteors, travel out of the city and to the country if you can. In the suburbs, just going from the front to back yard can make a dramatic difference as this will eliminate glare from those pesky street/house lights to a large extent.
Fortunately, this year's shower coincides with the waxing crescent Moon, which means that nature's night light will be a non-issue.