I can’t find a link to the clip, but there’s a scene in the Robot Chicken Star Wars episode of a couple looking at an apartment in Bespin. The guy toggles a light switch and complains that it doesn’t seem to do anything. The scene cuts and we see Luke Skywalker in the tube after having his hand cut off, and the trap door opens beneath him for no apparent reason…
I have three switches by the front door, one of which has no function that I know of; the others control lights inside and outside the door, perhaps it was for another light that was since removed (doubt it is for a walkway heater or anything like that).
ETA: Damn, I just realized that it might be for the nonfunctional outlet by the front porch, which I’ve never been able to figure out why it doesn’t work (last time I needed it, I used an extension cord from inside).
A switched exterior outlet in the front of the house would be really useful for plugging in Christmas lights.
We have a double switch by the front door. One turns the porch light on and the other does nothing
Or half of one?! Now I’m going to have to recheck.
You really ought to hook it up to a siren.
I had one in my laundry room, one of a set of double switches. Switch one controlled the light. Switch two, nothing as far as I could tell. All outlets top & bottom were hot, whether the switch was on or off, no extra wires in box for the ceiling fixture (not a ceiling fan, but I changed it out when I moved in). The switch itself was wired up to a live hot when I moved in so I removed the switch and put an outlet in its place instead.
I had one in my hallway that was a mystery for a few days - turns out it was a switch for an attic light that was burned out - non-obvious because the attic is just one of those crawlspace height type deals with no floor.
Or an engine block heater, assuming it’s near the driveway in a cold climate.
We had one in our last house that we didn’t discover the purpose of for 3 years. It turns out it activated an attic light (one that we also didn’t know existed) in the attic above the kitchen/dining room (the dining room was a relatively recent addition to the 100-y.o. house). We only found out what it did by accidentally leaving it on (not that we really knew which way was “on”…) and then seeing the light shining through the attic vent when we came home one night.
I’ve got several in my house. I’m pretty sure that they go to an overhead light that is designed to have a ceiling fan and turn the fan off and on.
If it’s switched, it doesn’t meet the 6 foot rule, so quite often they’ll wire it so only half is switched. When I’m wiring I’ll just put in a pair of outlets and flip the switched one “upside down”. I just wish Lutron would allow their dimmable receptacles to be used with dimmers other than their own. I just used my different brand of dimmers, which is techically against code since they’re not listed for use together, but is perfectly safe. I do like having virtually every light in the house on an electronic dimmer. With “soft start” no more “oww that’s bright” when turning on the light in a dark room and bulbs last a lot longer.
Cancel my mystery light switch. I think I’ve figured out what it is.
As it’s part of a double-switch, with another double-switch on the other end of the kitchen that DOES function (one for the ceiling light, one for the fan), I think it’s just a burnt out switch, or disconnected, or somewhat. And I thought about this today because of this thread, when I looked at the broken lightswitch, very dim…in fact, dark…next to it’s lit-up brother.
So, yeah. I think it’s just not wired. 
Yes, I have two. The stairs going from the 1st to 2nd floor has a double switch in both locations, but there’s only one light. And there’s another one in the back hall, that used to be for an outdoor light.
I had a set of three wall switches in the bedroom of my old apartment. The first switch activated the track lighting near the windows; the second activated the ceiling light; and I didn’t figure out what the third switch activated until I was on the brink of moving out, several years later. It was near the entrance to the room, and I came to the conclusion that it had once triggered a ceiling fan that had been removed before I came to occupy the apartment. That was not correct.
Inside my walk-in closet, there’s a small alcove above the hangers. I’d been using it as a storage space, because even as a fairly tall dude, there’s really no way to access the area without using a step-ladder. I found out when I was preparing to move, that at the very rear of the space, near the bottom right-hand corner, there’s a wall socket that only works if the third wall switch was flipped. Discovering this, I felt like I had learned everything I needed to know about the apartment, and satisfied all the requirements for being a responsible occupant. I was able to move out with a clear conscience.
However, I nearly always switch the non-working switch on before the real switch. Usually a 6:30 am before my wife wakes up. So, no thanks.
After living in my condo for nearly three years, I’m down to one. The switch is in the dining room. The switch immediately adjacent controls the dining room lights (with a dimmer.) Only thing left at this point is an outlet on a high ledge. And I have no idea who would ever use it - my dining area is fine, but there’s a high ledge - 10-12’ off the floor, easy. I can’t imagine what you would ever hand so high - maybe Christmas lights, maybe a neon beer sign (but I’m not about to hang that.) There is an outlet up there on the ledge, so the switch must be for that, but I have no idea what would ever go up there.
I do have an outlet. I do have a waterpik. I am laughing just thinking about this. The idea is hilarious.
The reality is that I would have either an angry wet husband, an angry wet teenager, or a facefull of water in retaliation, so, probably not. But it’s fun to think about. Even better than the whole rubber band around the vegetable sprayer at the sink!
I live in a 1900-ish Victorian sandstone house, and our main living room for some reason has no wired in lights, so we have to use standard lamps plugged in at the sockets. It’s probably had lights at some point though, as there’s a switch at the door, and another at the window. No sign of disturbed plasterwork to show where lights were removed, and all the other rooms have normal central lights and switches okay.
Very odd.
I mention the building date because I assume the house wouldn’t have had electric light when it was built, so presumbly lighting was retrofitted in the last 100 years, then removed from this room?
I have one in my living room that turned out to be a three-way switch for the ceiling light, which had been converted to a two-way switch at the other switch.
I was underwhelmed with that particular electrician.
Is the fireplace electric? Could it have been for a fireplace fan?