Answer is: other is lighthouse and it's foggy weather.
From #lounge and other logs:
<aloril> So Cool!!! <aloril> ---------- <aloril> <aloril> A young and foolish pilot wanted to sound cool and show who was <aloril> boss on the aviation frequencies. So, this was his first time <aloril> approaching a field during the nighttime. Instead of making any <aloril> official requests to the tower, he said: "Guess who?" <aloril> <aloril> The controller switched the field lights off and replied: "Guess <aloril> where!" <TheedMan> LOL <TheedMan> remembers a conversation from a navy warship asking the ship ahead of it to turn aside, and them them by (this was in the fog) <TheedMan> the navy ship eventaully, identifies who they are, and the other "ship" responds, we are a lighthouse... <malcolm> "This is the USS <??>, an American Aircraft Carrier, and we *demand* that you make way! <malcolm> "This is a lighthouse. Your call." <TheedMan> yeah, what he said <dcyoung> "I'm a lighthouse, sir. Your call."