that's because it's a long exposure. When you shoot action, you have to set the shutter of the camera to be very fast, otherwise things get blurred. However, when there is low light, you can achieve great pictures by using long exposures... meaning you have the shutter of the camera exposing the film for a long time, sometimes without a flash. Sometimes it's just for a few seconds, sometimes people will take pictures at night with hour long exposures.
The reason it makes everything look so wierd is because it picks up on the actual color of the light that is present. If the light is the slightest bit yellow, it will pick up on it, and the color will be saturated a lot more than if you used a flash. The green in the background is probably from street lights. I know I have seen green tinted street lights... you don't really notice how green they are until you see something like this.