light control
How about a light control where there are several push switches in a room. You can use a flash light bulb for demonstration purposes so there is no safety problem. If the light is on, pushing a button will cause the light to go out in a minute. If the light is off, pushing a button will turn it on. If during the one minute, a button is pushed, the light stays on. Next to each button is a led display that turns on during the minute delay.
This is very practical in a big room with several exits. There can be a button at each exit.