Never had so much fun until we bought our current domicile. 1890's era - wired that style, some upgrading/additions, but...
Wound up installing a new 200 amp panel, lots of new wiring, etc. Cut out all the knob and tube stuff, eliminated as much of the old style cloth covered romex(?) as possible. A couple of circuits we couldn't replace got GFCIs in series where it left the box.
Two serious gotchas were found - top of the stairs had a light with three way switches, one at the top of the stairs, and the other in the kitchen a room away. Took a while to figure this one out - the three way switches were wired to alternately switch hot and neutral back and forth. Finally figured it out and moved the kitchen switch to the bottom of the stairs.
Last one was the 3 car garage was fed from a splice in an external junction box (looks like a gutted early main panel), up through a hole in the roof and across to a hole in the (detached) garage wall, fed with 12-2 romex. Inside outlets and lights were daisy chained off this feed, and to top it all off, the idiot wired all the light switches to break the neutral.
