I am not sure who to give credit for this great idea. It has been called "Oliver's One Minute Flicker Light" It's cheap, quick and works great. It can be set up to run a single bulb or run multiple bulbs through an extension cord.. The beauty of this setup is that the power outlet gives the components the correct placement. Besides the two types of adapters, you need a "neon flicker bulb" and a one of those light sockets that turns a light on automatically at night. The cheaper this unit is, the better it will flicker. The more expensive units say that they have circuitry to reduce flickering. When assembled, the sensor on the unit must face the flicker bulb. To adjust the amount of flicker, twist the unit slightly away or towards the flicker bulb. If it is not obvious, the flicker of the small flicker bulb causes the sensor unit to "amplify" the flicker and cause large bulb to mimic the flicker. Be careful not to exceed the maximum wattage listed on the unit.
