Lightspeed

You get in to a car and travel at the speed of light. What will happen if you turn on the headlights?

Light always travels at c + your speed.  However, light will appear to travel faster or slower, depending on where you're going and how fast you're going in reference to where the light is coming from.

So...your lights turn on, and space deer fly in front of your car, then you slam into them in a fiery nuclear explosion.  Microwaved venison, anyone?