One of my favorite city adventures is to have a PC bump into a veiled person in the market place. Through amazing coincidence this person (a notorious thief) looks just like the PC. After the troublesome encouner, the thief decides to use this to their advantage, performing some minor crime without the veil. Of course, the guards and the robbed merchant upon seeing the PC will give chase. ANd to complicate matters, the thief's sidekick thinks the PC is the thief and want to know what the "real job" is about. Chaos and comedy ensues.