I'm thinking of running a D&D game (Moldvay-Basic) at a local convention and was thinking about the differences in designing an adventure for a regular gaming group, and one that's for a one-shot game lasting only an afternoon.

How do you approach adventure design for conventions differently from adventure design for an ongoing campaign?

Here's a good post on one-shot GMing (with some regard for design):

http://www.enworld.org/showpost.php?p=3007644&postcount=6

Great advice from Jeff's Worldwide Adventure Writing Month blog.

QuoteOn a more old school tip, here's David Cook explaining how the A series of modules for first edition AD&D were created (from the forward to the compiled A1-4 Scourge of the Slavelords megamodule):

First, each designer chose a low-level monster that would be the basis for his round: orcs in A1, hobgoblins in A2, and gnolls in A3. Next we decided on the number and type of encounters that would occur: nine encounters to fit the time limit of 3 1/2 hours. We guessed this would give a good team just enough time to get through every encounter.

...

We also set what would happen in each encounter. Thus we came up with the following list:

2 Traps
1 Trick to fool the players
1 Problem the players had to solve
1 Encounter with the basic monster of the round (orcs, hobgoblins, gnolls, etc.)
1 Ambush prepared by the basic monster of the round
1 Encounter with the basic monster and a friend (an ogre, for example)
1 Encounter with an unintelligent monster
1 Encounter with a brand new monster
1 Grand Finale

Using this list, we each went to design our tournament rounds.

Does that sound right to people?  All those things in 3.5 hours?

Here in Differentland, it´s 5 hours to a gaming slot at a con.

I´d still suggest having only 4 big encounters, though.

Quote from: StuartDoes that sound right to people?  All those things in 3.5 hours?

Keep in mind the tournament setting in that approach.  I wouldn't try to fit that much in 3.5 hours unless I was trying to seriously separate the wheat from the chaff.

I ran Basic/Expert Moldvay at a con 3 weeks ago.  I had an old school 10 level dungeon handy.  In 4 hours the PCs never made it past the first level and I don't think they had nine encounters.  If I had premade PCs they could have gotten to level 2 or three.  My OD&D event the year before had similar results.

In con games you can kill as many PCs as you want without feeling bad about it, but out of politeness you shouldn't start the carnage until the second half of the event, unless someone really earns it.

I actually didn't treat it differently than writing any other adventure when I wrote our GenCon adventures last year.

I made the adventure long enough to fill about 3/4 of the time slot we had, leaving time for picking characters, getting started, miscellaneous chatting and the occasional red herring, I scaled the balance, offering plenty of options for different numbers of players, since I wasn't sure how many we'd get and then I generated the PCs the players would be using.

That last part made it relatively easy. I didn't have to plan for wonky party compositions. I knew what they'd have available.

Maybe I should have taken the environment more into account, but I just tried to write the best one-shot adventures I could. The reaction seemed pretty positive overall.