The Elf, the Halfling, and the Fighter were arguing at first and spouting in-game racism at each other, which was great to see how easily they all got into character. But the Cleric calmed them down and said that they should work together and go find some treasure.
"Even if it's just for one dungeon, at least we'd have gotten something."
The players asked the other adventurer how much of the nearby dungeon he'd cleared out with his party, and the answer was that most of it was cleared but there were still some rooms unexplored.
At this point it was about 5 in the evening in-game so the players hiked for about a mile and made a campsite with the dungeon in eyesight.
The next morning, they went in and very quickly learned to check for traps and use a 10 foot pole; I had them go into rooms with disarmed, but still slightly functional traps which did no damage, and a room with a trapdoor that had been activated by a previous explorer.
As they went through the dungeon, they used the 10 foot pole to poke the walls and activated a secret button. It made a trapdoor open in front of them, but none fell in. It also caused the main door to the dungeon close (they couldn't see it but could hear it clank). At first they started to panic, but another, secret side door opened. They went inside and found a room with 3 Kobolds.
The Kobolds nearly killed the Halfling, who wasn't wearing armor, but he was healed back to full health by the Cleric. The Fighter then cornered the Kobolds and rolled a Natural 20. I went ahead and said all three Kobolds were killed by it, just because I wanted the guys to have a fun time. They all loved that and gave each other high fives.
In the next room, though, was a starving Vampire and a huge pile of gold. They fought the Vampire and killed it easily. They then got the gold and left the dungeon. But they also realized that they hadn't left the same way they came in. (2/?)