I am looking for a really simple way to cause the value in my RS_Incandescent shader to randomize in quick intervals, simulating the flickering pattern of a neon bulb. I was looking at some noise functions, but I don't see a way to control them to make them do what I want. Also I'm still kinda green in VEX.

Any ideas are appreciated!

You could use an hScript expression in the intensity field. Try something like this…
This will give you a random value per-frame between 0.15 and 1.15. Adjust values as needed.