What the !%#&* is a Stairmaster?

Lizzie: "You didn't say anything about exercise."

Me: "I'm sure I mentioned it."

Lizzie: "Not climbing stairs you didn't".

Me: "Well, they're not so bad."

Lizzie: "You're not the one climbing them."

Me: "But you're doing so well on your diet -- a little exercise will help even more."

Lizzie: "When I come back down we're going to talk about this."