What did people use to make night-time bright with the flip of a switch?

The light bulb is what let people make night-time bright with the flip of a switch, since it produces light by passing electricity through a small filament or gas inside a glass bulb until it glows brightly. This meant homes and streets no longer had to rely on burning candles or oil lamps to see after dark.

The telephone lets people talk across long distances, and the bicycle is a way to travel on two wheels, neither one has anything to do with lighting up a dark room, so they don't fit what the question describes.

Before electric light bulbs became common, people used candles or gas lamps for centuries, and switching to electric light was one of the biggest changes to everyday life in modern history.