The remains of a small skirmish. Be sure to have several dead still steaming in the morning mist (ie still warm). It works best if the PC's are at war with both sides (so they are not sympathetic to either side), then have a survivor found from each side. Be sure to have both warriors promise whatever if the PC's will save them and eliminate the other. Also be sure to imply that someone will be coming back here. Give experience if the Clerics administer last rites, and if the PC's are sufficiently solemn. There should be NO battle here. Just role playing.
I pulled this one in one of my fantasy campaigns, and the PC's saved both survivors, only to find that the allies of one of the survivors had gone on to the next town and looted it for supplies. (The nearest town happened to be a PC's hometown.)