If my fiancee Liz was not on a trip with our camera, I would have snapped a picture of Arthur tugging at the door knob on the front door last night or Beowulf trying to pull the knob on the hall closet this evening. For the past few days, the two of them have been leading against both the front door and the closet door, meowing up at something, and then reaching their paws up to try to turn the knob.
Fortunately, the front door is always locked and the closet door knob is actually just a handle that can't be turned. However, I'm starting to feel like I did the first time I watched 2001: A Space Odyssey and I saw the scene where the first ape picks up a bone and decides to use it as a weapon. They are trying to learn to turn a door knob. It may not be long before they successfully open another door, the door to the bedroom.