Here is a piece of history that really deserves mention. One of those things that is just so brilliant you wonder why you've never seen such a thing before. So when you are carrying something from the kitchen to the dining room and there is a door in the way (yes a door - some people like the idea of having a barrier preventing their guests from seeing what a mess their kitchen is) it would kind of be a pain to need to use your hands to open the door. Okay you say - just make sure that you don't close the door all the way and then back into it. Right but then you have to either close it behind you again or else face the same problem when you are coming back the other direction if you have an automatic closing mechanism on it.
Enter the double action hinge. Engineering marvel and 8th wonder of the world. This amazing device allows a door to open in either direction, closes automatically or stays open if opened all the way. So you can back into it in one direction watch it close and then back into it in the other direction and watch it close again. If you're really bored you could do this all day and get a good workout.
What is really most amazing about this particular implementation of this great idea is that the entire mechanism is hidden out of sight behind a couple of plates at the bottom of the door. Pure genious. Shame you can't seem to get them like this anymore.