In our apartment, for the last few months, my wife and I are being puzzled by strange sounds coming from the dining area while we remain in the bedroom at night. The first time we heard, I was quiet. Then my wife said, "Did you hear that?" So, it was no hallucination whatsoever. It is a distinct sound of a spoon stroking a glass. Sometimes once, sometimes twice. These are the confirmed facts about the surroundings: 1. At night, after dinner, we leave our glasses on the dinner table. 2. The glasses are kept far enough from one another. So, no earthquake in the world can bring them together for mutual bombardment or anything like that. 3. There are no spoons on the table. 4. Our mobiles/tabs do not have any settings for notifications, emails, messages, that would sound like that. 5. We reproduced those sounds by one of us hitting a glass with a spoon on the table and another staying in the bedroom in order to sense any difference. There was no difference. The sounds definitely originated from the dinner table and, more precisely, from those glasses. 7. Other possible sources are compressors of the fridge, air cooler, etc, but they do not sound like that. 6. We do not drink. So, we do not get drunk. We do not take any powerful medication. We have no history of hallucination. 7. Those sounds are so sharp and distinct that they just cannot be coming from neighboring apartments in the building. So, would any physics enthusiast attempt to explain what is the physics behind those sounds being produced from glasses kept apart from one another on the table?