Speaking of heating up, I'm at work, and we are in habit of plugging in the block heaters on our cars when we come to work and flicking down the circuit breaker switch. Then two or so hours before the shift ends, one of us goes to the parking lot and flicks up the circuit breaker switches for every one.
The person who does this, will then inform of this to the other persons in the circle. The mime we use to do this in our hard-to-hear surroundings all in all probably is not very safe to work.