you do the household chores you have been lazily putting off simply because doing them will heat the house!
So far I have washed 2 loads of white laundry on HOT, dried them using our electric dryer with the vent venting INSIDE, and started the dishwasher. I'm thinking I should also make some soup stock, too... just to have on hand. That will warm the house up.
Have I turned the head above 54? No... I'm too cheap. I'm not touching that thermostat!