70年代後半にパッと現れ、以後フォーミュラジョークとして燦然と輝き続けるlight bulb（lightbulb) jokes。
その公式とは：

How many ______ does it take to change a light bulb?
Don’t know. How many?
Five. One to hold the bulb and four to turn the chair.

空所にはジョークの的になる人々を納める。

「電球を入れ換えるのに＿＿＿だと何名必要？　さあ、何名？　５名。1人が電球を持ち、残りの４人が椅子を回す」という視覚的ギャグのきついもの。それを元に大量の作品が発生。原型がエスニックなものだったこともあり、皮肉なものが大変多く、社会を映す大人のジョークとして現在に至る。以下英文解釈用に数例。腕試しを。

How many bankers does it take to change a light bulb?
Don’t know. How many?
Four. One to hold the bulb and three to try to remember the combination.

How many Californians does it take to change a light bulb?
Don’t know. How many?
Three. One to change the bulb and two to share the experience.

How many Japanese industrialists does it take to change a light bulb?
Don’t know. How many?
Three. One to make sure the new bulb is not foreign, one to change the bulb, and one to look into the export potential of the old bulb.

How many bureaucrats does it take to screw in a light bulb?
Don’t know. How many?
One, but he’ll need two outside consultants to help.

How many Frank Sinatra fans does it take to change a light bulb?
Don’t know. How many?
None. They love Dancing in the Dark.　 (K.T., hopefully)

How many grocery store cashiers does it take to change a light bulb?
Don’t know. How many?
None. They wont’s even change a ten-dollar bill.

How many software engineers does it take to change a light bulb?
Don’t know. How many?
None. That’s a hardware problem.

How many Zen masters does it take to change a light bulb?
Don’t know. How many?
The Zen master is the light bulb.

そして
How many Japanese (people) does it take to change a light bulb?
と、にやりとした表情で訊かれたら
One.
と答えるのもひとつのユーモア。４の５の言わせぬという意外な気概を演出。