I got arrested in Ecuador for being in a park after a curfew and not having any ID on me with five of my English compatriats. I spent 6 hours in a police courtyard with the slime of Quito, under armed guard. Two of my friends were allowed to go and get copies of our passports, but got lost on the way to our hostel AND back. We were forced onto the Prison bus, but saved by the chief of Police and then the terrible two arrived and saved the day.
Great fun looking back on it, but a little scary at the time.