The system: D&D 3.0, because that's what the generators use.
Tools:
- Characters: http://www.hailscape.com/
- Dungeon: http://donjon.bin.sh/d20/dungeon/
- Players: As many as you can fit at your gaming table. The more the merrier.
Basis for the story, in a very small back woods town, a group of adventurers listens to the ramblings of drunken man as he reveals to them a dungeon filled with riches and wonder on the outskirts of town in an abandoned and broken down temple. The temple is a one hour horse ride from town, which is always an uneventful journey.
This is a very good way to force players to move outside of their comfort zone and also a great way to practice enforcing things like languages and alignment restrictions. If the players can some how muster together long enough to accomplish something, they will find an collapsed entrance at the back of the temple that will reveal the random dungeon's entrance.