So, I'm currently working at a summer camp, and some of the camp staff expressed interest in a D&D game, so I obliged. Here's how it went:
They were hired to retrieve an artifact from a friendly community of kobolds. On the way, they encountered a heretic fleeing the imperial enforcers, begging them to lie about which way he went, offering them all his wealth. The party agreed, and he gave them a gold ring with a fat emerald. The party was good to their word and lied to the knights. (They briefly considered attacking the fugitive and taking his money just to be rude, but (CORRECTLY) reasoned that anyone with sixty horsemen after him is probably dangerous)
Then they got into the dungeon. (Unbenknownst to the party, the artifact had corrupted the kobolds, and so the peaceful community was now a warzone between the remaining kobolds and their goblinized former friends)
They moved along cautiously and well until they encountered some giant foot-long mosquitos (random encounter.) They killed one mosquito and their assassin chased the rest into the darkness where he fell into a pit and was incapacitated. The noise also alerted the goblins in the next room. When the rest of the party caught up, the goblins shot the fighter and dropped him in one. The mage jumped into the pit and tried to perform triage on the assassin (His mortal wounds roll ended up being damaged heart and lungs, which I explained to the party as lots of broken ribs from his fall) while the elf dragged the fighter away. They made it out but the fighter promptly bled to death. (Somehow the mortal wounds roll said both his arms were broken, but I didn't mention that to the party, since he had one round to live anyway) The mage and the assassin were taken prisoner (I can't really see the goblins treating the assassin's ribs, so they'll probably eat him. The mage could yet be rescued though)
I felt kinda bad about the level of fatality imposed, but everyone had a blast despite the fairly brutal cascade at the end of the session. The mage's player specifically came up to me and said that she had no idea D&D was going to be this much fun. The closing note of the session was a sad laugh when they realized the fighter's pet chickens were orphans now. (He was really excited about the prospect of fresh eggs during the journey.)