Why do we need a hot water heater?

If it’s hot, it doesn’t need to be heated.

What do you get when you cross a parrot with a centipede?

A walkie-talkie.

An English teacher asks Little Johnny: “Make an opposite of this sentence... ‘Kids in the dark usually make errors.’”

Little Johnny: “Errors in the dark usually make kids."

What's the difference between a vision and a sight?

When my wife gets dressed up for a party she looks like a vision and when she wakes up in the morning she's a sight!