Several years ago I spent a few weeks in a country that as far as I could tell didn't have a "coffee culture" and all that was readily available was packets of instant coffee. I hunted around and found a vacuum packed brick of ground coffee at a shop, but didn't have any equipment to brew it. Then I worked out that you can throw some in a glass bottle, pour in some hot water from the kettle, let it sit until everything settled to the bottom, pour out the liquid, and "voila!"

Later on the trip I bought a Turkish coffee maker, which works on the same principle, so it's not so much an innovation as it is a hotel survival tip.