The two clues as to where I am today should have come when I was about to get of the train this morning and found myself reaching into my pocket for my car keys. Then a few minutes later I noticed myself putting the key to my office back into my pocket as I was walking between the outside door (badge access) and my office. Clearly, part of my mind didn't want to work.
Then I got the preliminary "requirements" from the users of the large tool I'm supposed to take over maintaining with a major redesign. The good news is that this looks like a sizable project. The bad news is that this looks like it is going to be a sizable project. On top of that, it will be pushing me into new areas, but not ones I mind too much being pushed into.
Of course, if anyone here wants to offer advice on where to go for help with getting up to speed on this stuff, I won't object.