Spot Light
Spot lights appear in the scene as a yellow wireframe cone.
You can change the direction of a spot light by rotating it.
You control the way that the spot light effects the objects in the scene with the two sliders that appear on the Spot Light tab in the Object Properties window when the spot light is selected.
Use both of these controls together.
Note that spot lights work best when you shine them on planes, walls or floors with Complex checked.