Simply keyframe the color of your light source property over time.
Flickering will be kind of laborious, because you have to change it manually.
Cheers
Frank
Do you have auto-keyframing on?
If it's off, and assuming you haven't tried this, make the color of light one color, hit record, go to next frame on the timeline, change the color, hit record. Make sure you have "Key All Other Parameters" turned on. That's the P near the auto key.
That is not necessary! Just make a right click and record what you want.
If you just care about disc space=No.
If you like it clear&clean=Yes