You turn two light switches on..

Then, quickly, you turn one of the switches off and run downstairs..

One room (which will the switch you left turned on) will be lit, one room (which will be the one you never touched) will not be lit AND the light bulb will be cold, the other room (which will be the one where you quickly turned off the switch)will not be lit BUT the light bulb will still be a little warm.

Using those calculations you will be able to determine which switch goes to which room with one trip down the stairs.

Fuck yes bitches!

$500,000 comin my way.

Holla at cha boobies.