I ended up doing a lot of cleaning.
I think I filled three 55-gallon trash bags, stuffed full. Plus another couple of boxes of crap, an old TV set that's been in the basement forever, an old sewing machine table that has seen far far better days, and some more stuff... I figure it's 2-3 cubic yards of crap just tonight.
I also managed to set up one stand-up workbench, not in the lab but in the workshop part of the basement.
There was dust and mildew and just general grossness. I'm going to have to do some mold killing in the future.
But I got a good amount accomplished. Unfortunately it took me all night, so my sleep schedule is uberfukt.