Saved by Super Dog....

Yes, it's 1:30 in the morning.  And life is once again winding down after averting a potential disaster.  Maggie had the indecency to start barking at the front door, the result of which was I had to get out of bed to see what evil was lurking (or who was toilet papering the neighborhood) or other nefarious night life.  Sure enough, there was nobody at the door, and life was quiet on the street, so reassuring the dog, I went back to bed.

Then there was a sound, something like a toilet running, but not coming from the toilet.  It sounded like it was coming from the sink... only lower.  Heading downstairs to the main level, there was no sound of running water coming from the bathroom.  Strangely there WAS the sound of water running in the family room.  Strange, because the family room has no plumbing fixtures, and hence no need for running water.  To be precise, the water was running out of the ceiling onto the carpet - not good as the carpet does not have a drain and the ceiling is not equipped with a faucet.  Back upstairs and under the sink, there is water running.  Seems like the feed from the hot water line for the sink decided that it wanted to not play well with the rest of the bathroom plumbing and and taken the night off.  Hot water was coming out of the partially disconnected feed line to the sink.  Solution: turn off the water, mop up, and go back to bed.

Damage: there's a couple of spots on the ceiling that will need new popcorn sprayed and paint applied.  The stuff under the sink was mostly in sealed containers, so adrenaline rush aside, we got lucky.

And thanks to the dog for barking at "nothing" and waking me up.