The Quick-and-Dirty (and OCD-approved) way to write adventures
UPDATE: 5/9/2011 (revised template based on Chimera Basic 5th Printing)
Gamers my age grew up with adventure "modules," which were fairly extensive write-ups filled with all sorts of information needed to run a scenario. Juxtaposed to these multi-page volumes were Adventure Record Sheets—early forebears of the One Page Dungeon Template that's gaining popularity today—which encouraged you to cram every piece of relevant scenario datum into little boxes slightly larger than your thumbnail.
Full, descriptive write-ups make for a good read, but they're not practical for the busy GM. They take too long to write, too long to read, and (assuming you're already familiar with your own campaign) provide more information than you actually need (or use) at the gaming table. Given all that, Adventure Record Sheets make a ton of sense for the GM who has a scenario in mind and just needs to organise his notes. But their truncated format isn't always GM-friendly, and (with all respect to David Bowman aka Sham), the One-Page Dungeon Template is a little too free-form for my OCD.
Enter the Adventure Template, which provides a short-form outline for a scenario. This format captures everything you need to run an adventure. Use one template for each locale in a given scenario: a forest, a swamp, a tower, a ship, a village, or (of course) a dungeon level. String multiple templates together to form a larger adventure or a series of related scenarios. You can even use the template to organise your notes about non-adventuring locales, like the PCs' homebase town, a city quarter, or a frontier stronghold.
A Tour of the Template
The template is divided into sections, which you can complete using the guidelines below. For illustrative purposes, I've provided a sample template based on the adventure, Apocalypse Ants, included with Chimera Basic.
It's helpful for each of your scenarios to have a title, mostly for organisational purposes. Write this in at the grey banner at the top. If you're like me and save every scrap of RPG-related material you write, include the date—when you show your grandchildren, you'll appreciate knowing when you first created this masterpiece.
The map section is provided as a 20x20 square grid or a sub-hex map in which you can sketch out the adventure's locale (be it wilderness, interior floorplans, or a dungeon layout). Each map should covers only what is described on the template, so if you have a multi-level dungeon, use one template for each level.
Every adventure begins with an adventure hook, typically a single sentence that describes a problem and motivates the characters to get involved. The benefit of including the hook is that it keeps you grounded as you run the adventure—while the scenario is bound to take unanticipated turns, the hook can help keep you (and the players) on task if you feel that things are running too far afield.
Background & End-goal
The background is a fleshed-out version of the hook, and it may include secret GM notes about stuff the PCs aren't immediately aware of. The characters should figure out the background details as they push through the adventure, but that's up to you—for now, it's important that you know the behind-the-scenes details.
The end-goal consists of the "victory conditions" that define the adventure's conclusion. In other words, what do the PCs have to accomplish in order to finish the scenario, collect their reward, and roll to advance?
What the PCs get for finishing the adventure. This could be monetary rewards (treasure or commission) or other forms of wealth. You should also include any special rewards here, in the form of adventuring goals that garner a bonus to the characters' Advancement Roll at the end of the mission.
While not always necessary, it's sometimes helpful to note possible outcomes of the PCs' activities—what happens if they survive and how does it impact the setting and its inhabitants? Finally, it's a good idea to consider possibilities for follow-up adventures, though I'd suggest not planning too far ahead.
This is a list of what the PCs encounter during the adventure, keyed to your map. Include only enough information to run each encounter: monsters and NPCs, general response to PCs, high-level tactics, and any particular bits about the map location that might be important to the PCs.
A roster of monsters and NPCs who oppose the characters. What role do they play in the adventure, and what drives them to oppose the PCs? The form is customised for Chimera, but you could easily revise the headings for your own purposes.