If you live in a city in which taxi cabs are leased to the drivers, you might want to look into it. Many cab companies lease on a "shift" (24 hours give or take) or "weekly". The great thing with shifts is that you can come in whenever you want, even after not driving for 2 months with some companies. It boils down to setting your own schedule. Obviously you don't drive for the full 24 hours, they assume that you will take your cab home and sleep for a few hours. During my CFI days, I would often give lessons during my cab shift. Just drove the cab to the airport, did the lesson, and got back in the cab for more runs. Depending on the city, you can make decent money. Just talk to a taxi driver.