Ouf, has it really been two months since we last talked? Sorry about that. I bring you good tidings and a fun DIY to make up for it.
Back when I first adopted Bruce and was living in Seattle I did a similar project. I installed a bi-fold door in the kitchen. It was easy and it kept the cats from being in the kitchen when they weren't invited. The same problem (having cats) reared it's ugly head again so I decide to give it another go.
Here's the kitchen doorway before:
There's an odd little latch on the frame and a weird little knob on the top of the frame that makes me think at some point there was a door here. Possibly a sliding door. Every inch of my being has wanted to hack open the wall to see if indeed there's a pocket door hiding in there. But alas making my own was a lot easier and probably a lot cheaper than plastering up the mess that would entail.
So for a totally of $60 dollars ($66 really, I think) I purchased a set of bi-fold doors and chalkboard paint (both the prices in those links are not what I paid. The doors were $40 something and the paint was $9.98) and three black hinges. The paint was really great. Three coats was all I needed. Chalkboard paint is sensitive though, you have to let it cure for three days then wipe chalk all over it and rub it off and you're good to go. Science.
Now that there's a door it will make it easier when I finally give in and paint the kitchen. Cats are nosey you guys.