An idle brain is the devil's workshop.

An idle brain was the devil's playground, and she was nothing if not idle.

Davy said impassively, "The idle brain is the devil's playground."

What seek ye there, Ye restless thoughts and busy purposes Of the idle brain, which the world's livery wear?

He rather liked it; ah, the idle brain again, he thought, that he could like something at such a time.

The idle brain is the devil's playground, he chuckled.

The idle brain is the devil's playground, you know.

When television is such a mathematical word problem, it hurts the idle brain.

As was typical of the idle hollow brains, however, they thought they were proprietors of all the worlds' wisdom.

An old saying tells us that an idle brain is the devil's workshop.