Jason Morningstar has put together something pretty amazing: The Slave-Pit of Drazhu, an adventure designed to be played at a convention in two hours. In addition to describing the pit itself, the adventure includes a new class just for experienced players and a huge selection of items.
Tell everyone they have been enslaved by the evil lich Drazhu and his vicious minions, who have put them to work digging tunnels to expand Drazhu’s underground lair. An enterprising dwarf, now dead, managed to make a detailed sketch of the complex. Life sucks, bad. Play it up!
Put the map on the table and answer any general questions about it. There’s no mystery to the layout of Drazhu’s lair; the exit is well known.
Hand out playbooks however you like. Four heroes is a good number, the classic adventuring party, but if you have a big crowd add up to four more pit slaves. They are really fun!
Explain how to apportion stats and build characters generally. Tell them to ignore listed bonds and starting equipment. Tell them not to think about it too hard and to hurry up generally.