So what would you folks like to encounter when you stumble upon a ruined city out in the wilderness?
One of my favorite troupes has to be the Death-cult residing in ancient ruins preforming horrible rituals for their fiendish deities. Players can choose to charge in with spell and sword ready or kill of a few guards and sneak in wearing their robes. They better not waste time though, or the horrible ritual to summon [insert elder God here] the Eater of Worlds! I'm really thinking somewhere between Col. Kurtz and Temple of Doom here.
Another possible fun encounter would be a Necropolis