If you've ever seen photos will cool looking light streaks in them, they are what is known as a long exposure photo. How it works is that the shutter in the camera is left open, leaving the sensor to absorb light for a relatively long time. You can see this effect in the above photo in the brake lights of the car in the foreground. The car pulled forward during the time the shutter was open, leading to the streak of red light. There are tons of awesome ways to use this technique in photography so get out there and experiment!