So I'm on the tube home and go to pick up a newspaper left on the ventilator thing behind the seats, only to find a sleeveless DVD case. I open it up and, what a surprise, there's a vaguely sexual DVD in it (The Essential Lover's Guide rather than some real porn though). I burst out laughing, had a look round and decided no-one on the carriage could have possibly misplaced it. Before anyone asks, of course I took it.
Tell me about a time something so unlikely, stupid or potentially compromising happened that you concluded someone must actually be playing you.