Apologies to any who have tried to call me in the past several days. I had a short in my phone line caused by an interesting combination of some sort of animal pee, dust, and moisture that was just enough to wildly spark whenever the phone would try and ring, and stay ionized long enough to fool the phone company into thinking it had connected, then lose the ionization in just over 2 seconds. It's one of the more freakish circumstances I've ever run into where the combination of stuff was just right to make it fail for incoming calls only, but outgoing calls were fine, and the only time there was a failure was on an incoming ring.
Technically, it makes sense: the normal unloaded phone line voltage is 48 volts DC, and the ring signal is a 20 Hz sine wave at 105 volts superimposed on top of that. That would actually peak out at 153 volts, which was apparently enough to kick it over the knee point. I actually watched it spark.