The most common format of a lightning round is in a question-and-answer game, to answer as many questions as possible within a given time limit.
The term "lightning round" is usually reserved for a single round in a game whose normal gameplay is untimed.
Lightning rounds are often used at quiz bowls.
In television, a lightning round is usually accompanied by an indicator of the time remaining, and is commonly presented with some increase of intensity, such as a change of lighting, or sound effect (such as a ticking clock), or musical cue.
The term was also famously used in the Friends episode "The One With the Embryos".