lightbulb effect

im making a horror fps game in unity and i would like to know how to make my lights flicker every few seconds.

does anyone know how i would go about doing this?

http://unity3d.com/support/documentation/ScriptReference/Light.html

http://unity3d.com/support/documentation/ScriptReference/Light-color.html

And use the yield WaitForSeconds(NUM_SEC); between the actual dimming and what not...