So having used my simple foam lightsaber successfully in a game of Humans versus Zombies (albeit with much resoldering of the core LED string), I'm hoping to have upgraded it a little by the time next game rolls around. What I'm looking for first before anything else is a way to make the sucker flicker randomly without having to resort to buying a circuit board that does more than what I really need it for; that is, to make the saber flicker like a, well, saber.

I have a bunch of LEDs in parallel drawing 20 mA each and would like to find a way to make them flicker randomly without breaking the bank (or having a weak connection that also breaks). Suggestions?

(If someone could also tell me the cheapest way to add sound to a saber, I would be much obliged. I've heard that gutting cheap toy sabers is usually the way to do it...)