I have short legs. When I'm sitting and I put a laptop on my lap, it tends to slide off.

To address this, I got a Silpat baking mat to put on my lap, under the laptop. I've only used it a few minutes, but so far it's quite comfortable with excellent grip, and my MacBook Pro hasn't budged.

I don't think the mat is intended as an insulator — indeed, I assume it's supposed to transfer heat from your baking pan to your cookies — but it does protect my legs a little from the heat of the laptop's aluminum bottom.

As an extra bonus, this helps me keep my wrists at a good angle by having the keyboard very low.

I wonder if I'm the first to think of this.