Next thing I know, it's dark.
Considered remaining abed, but then remembered I had to deal with that rotten spot by the back door. See, they uncovered a place where the plywood rotted, and I know why: sometimes rain blew in on that spot, and soaked through the carpet, and ruined the wood underneath. So I levered myself out of bed and did the following damage:

As you can see, the floor surface has been painted with some kind of sealant, which is why it's grey. The rot extended through to the subfloor.
Replacing the subfloor was a nightmare I didn't want to contemplate. The part of it which is exposed is a piece between the riser on the foundation and the eastern-most floor joist. To do a proper repair, I would have to lift more of the 5/8" plywood so I could replace perhaps a 5x3 foot area of the subfloor. I have 3/8" plywood on hand, so that wouldn't have been a problem, but both floor and subfloor extend under the drywall, and this job had already turned into a bigger mess than I'd anticipated.
...but it's 5/8", not 3/4". I bought, the other day, 3/4". Damn it.
Went to Menard's for plywood, and I found that they do in fact have smaller pieces than 4x8' sheets, so I bought one of those. 2x4', perfect--fits in the back seat, even.
Got home and returned to work. Jimmied up a guide so I could cut a straight line across the plywood, cut a 9.5" piece off...and for grins, measured the 4x8 sheet I bought the other day. 5/8". *sigh* Well, it doesn't spoil or anything.
Test-fit, and it wouldn't quite go in. Found that I needed to trim exactly a saw blade's width off the side by the back door, which stands out just a hair. Eyeballed that cut, and it fit exactly with a little bit of persuasion. Nailed it in, reinstalled the woodwork, and cleaned up my mess.
The result:

That looks like a professional did it. I'm kind of agog that I managed to make a piece of wood fit so precisely, but I did.
...and tomorrow that lovely-looking repair gets covered by carpet, so I'd better gloat over it while I can. Heh.
* * *
While at Menard's I looked at their train aisle.
What caught my attention originally was the endcap of O-scale railroad cars of various kinds. I first saw it before Halloween; when I bought the 4x8' sheet of plywood I gave into temptation and bought one, a flatcar with a tarped load. Not very Christmasy for my Christmas train set, but oh well.
Today I looked past the endcap, and ended up going into the aisle itself, and was amazed at the plethora of stuff they had for both O and HO scale. Buildings, track, and more. I ended up buying four 3' straight sections of O track to add to the Christmas train set. (No turnouts that I could see, worse luck.)
Mrs. Fungus originally bought me the train set with the occasional expansion in mind. I want to go back one more time and get two more of those 3' sections, but that can wait until my first paycheck. Heh.
* * *
Speaking of which, now I'm just waiting to hear what my start date is. Monday would be fine. We'll see.