Would be interested in hearing what strange/odd electrical things you have found hidden inside walls, boxes, etc. I have found an out of service light switch in a handy box coiled up inside a drop ceiling & have seen terminal blocks & test switches in the middle of cable trays & bottom of control cabinets.
Most of the actual electrical stuff isn't so funny or too memorable - the other type of finds are....
Dead (decaying) rat latched on to chewed and shorted NM inside a wall - same for squirrel. Various dead mice.
Horribly misused extention cords. Not so funny - but hillarious what people think can be done with them. As well as other laughable wiring methods too numerous to list.
All kinds of nasties found in J-boxes. Hornets - no thats fun. And slugs, (Cousin of snail - not to be confused with KO slugs) found a christy box full of them once. Black widow spiders. Panel full of roach bodies - I broke open a breaker in that same panel to find it packed so full with roaches that I beleive to caused its failure to operate.
Other than just historical ditritus left in crawl spaces, like 1800's shoe shine kit, pottery and plate chards from the 1906 quake - melted bricks from same. Cold medicine from 1928. I found several pages of newspapers of various dates. One from the 30's stating that "war in europe may break out any day now..." Had a helper run into a hibernating rattle-snake - that was fun....
And my all time kicker - a whole bar hidden under a house in the Fillmore district of SF. Due to the hidden entrance - possibly a forgotten speakeasy from prohibition. The owner for over ten years had no idea it was there until we tried to drive a ground rod in the garage and it dropped though to this hidden room. I have learned that they subsequently had to do major foundation work due to this neat little addition. It is now ironicaly a wine cellar and still has the same bar newly refurbished.
Mark Heller "Well - I oughta....." -Jackie Gleason
About 10yrs ago I was working with my uncle doing a remodel in a basement of house. I removed some ceiling tiles near the center I-beam of the house and....almost got my teeth knocked out by about 8 porno VHS tapes. I got hit in the head by one of them. Two minutes later, we heard the MRS. coming down the stairs. We started launching them back into the ceiling. It was either her husbands or her teenage sons/ and if it was hers, "good for her.". We never laughed so hard.