We stayed in a hotel over the weekend and ended up in an ADA-accessible room. It was a bit more spacious, but other than that, there was nothing out of the ordinary, or especially green about our room, but we did use less water in the shower thanks to the showerhead...
It's a super simple idea: there's a push button on the shower head that turns the full flow down to a trickle. It's the same idea as the tap saver, just for a shower instead of a faucet.
So with the usual long, hot shower, we saved a bit of water by hitting the button while soaping up. It has a nice strong spray, too.
Alsons seems to be the manufacturer of these, and they're pretty affordable: less than $17 at Home Depot.