Since I started my West Marches campaign I've had to roll with the blows, so to speak, and come up with notes for an evenings adventure in a hurry. This is how I do it:
I usually have at least an inkling of what my players want to do, as is the nature of
West Marches-style campaigns. So checking our
group usually gives me a good base to start from. But of course there are days when you just blank. That is when I consult...
S. John Ross' Big List of RPG Plots, or, if I'm really stumped,
The Moldway Adventure Creator. That'll set me up with the basic outline.
Then I pour that through
Dr. Rotwang's patented adventure funnel to get the plot in shape.
Of course, you'll (sometimes) need a dungeon map. For that I use either the very awesome
Skeleton Key Games Dungeon Generator or if I have no time at all,
Janis Buck's Dungeon Generator.
And that's my setup right there.
How do you guys insta-prep?