The best I can come up with happened in Athens. We were on a schooltrip to Greece, and on our way back one of my mates kept setting off the detector; he had to remove all metallic objects, including his belt. Now, he was wearing one of these huge baggy pair of jeans (like skaters used to wear alot), and while walking through the detector set it off again. He raised his hands to be scanned again, whereupon his trousers promptly positioned themselves around his ankles! Luckily I had my camera ready...