Radio Controlled Electronic Switch can be used to switch on/off anything electrical, whatever it is.
http://www.uoguelph.ca/~antoon/gadgets/rc-sw.htm
http://www.web-ee.com/Schematics/Voltage%20Multiplier/Cockroft-Walton.htm
http://www.uoguelph.ca/~antoon/circ/alt1.htm
http://www.mitedu.freeserve.co.uk/Circuits/Interface/ir_switch.htm
switching handheld units on and off with a pushbutton switch is a desirable feature but needs some thinking.
http://www.e-insite.net/ednmag/archives/1997/092597/20di_05.htm
This is a data latch and indicator which also is a data switch and has a bidirectional input/output port which can be read or switched.
http://www.4qdtec.com/dsw.html
http://www.zen22142.zen.co.uk/Circuits/Switching/coldsw.htm
A switch which changes state each time it gets an impulse.
http://www.4qdtec.com/ics.html