I found a couple of really interesting things while I was house hunting.
A townhouse I seriously considered buying had the master suite as the only room upstairs; the other bedrooms and the public areas were downstairs, which seemed like a good setup, however, the master bedroom had an opening in one wall above the kitchen, overlooking the living room. That opening meant that the master bedroom had a view of the living room and people in the living room could look up into the master bedroom. Also, the stairs to the master were a spiral staircase, so the only way to get a bed up there would be to hoist it through the opening in the wall above the kitchen.
I saw several condos that included a split bathroom: the toilet and shower/tub were in a room with a door and the vanity was outside in the hallway. It's the sort of setup you see a lot in hotels and sort of made sense if you were attempting to share a bathroom with several people, but invariably, they all had light carpet in the hallway that ran right up to the bottom of the sink. I couldn't imagine how much water had been spilled on that carpet. I think the weirdest part of this one was how many condos seemed to have this. I'd never given much thought to it before but after seeing five or six in a row, it became a major point on the "no need to see more" list I had.
A friend of mine has a house that has a really weird feature. They have a round alcove off their living room that they use a breakfast nook, which is really cool, and from the outside it looks like it's inside a turret that goes up higher than the house with a pointed roof. I assumed it was just an attractive feature and didn't think much of it, until one day I went to visit and when I made it to the living room, my friend was hanging upside down from a trap door in the ceiling of the breakfast nook. When I questioned him, he came down and gave me a tour: turns out there's a whole second floor of the turret, but it can only be accessed by climbing through the back of the upstairs linen closet and creeping down a long, low-ceiling-ed hallway. They cut the trap door in it so they could do the finish work on it to turn it into a playhouse sort of thing and it's got carpeting and drywall and wall sconces and it's furnished almost entirely with beanbags so it's a perfect reading room.