Well I was thinking that fifty pounds off the gas board.

Can you think about it just off the top of your head?

If you even think someone's trying to break in, fire off a round.

I had been thinking of her on and off all day.

I can think of a couple right off the top.

It's nice for letting people think that something's off the record.

"Did you just think that up off the top of your head?"

That's really all I can think of right off the bat.

You don't have to think so much off the top of your head during a game.

He halted to smoke and try to think, off the road a ways.