Some good ideas, I forgot how to wire a polarity reversing switch, found how-to info on a website. Ace R/C used to sell tapered egg-shaped cam things with set screws that fit on a servo operated pushrod. I used three of them to actuate microswitches to turn on/off three separate lighting circuits sequentially. I guess you could grind wheel collars or glue egg sinkers onto the pushrod in the right positions to do the same thing. A servo arm can push one or two microswitch buttons or arms in a compact installation. Boats seem to encourage ingenuity. Maybe somebody could set up a "sticky" on this forum ideas like this. Other ideas are motor and other sound systems, smoke systems. I made a little portable TV set with a GOW bulb inside and a piece of color slide film for a picture.