My favorite hotel design feature

of the most recent trip was one I've seen before in Europe but not yet in the U.S.: To enable the power in your room, you have to put your plastic card key in a slot right by the door. When you leave, you take your key, and out go the lights. It's a wonderfully simple way to reduce energy consumption, and it does so at no real cost to the user.

I wish all hotels here would adopt it.