How do I write a Character-Provided Event?

When sitting down to plot a character-provided event, what process do you use to lay things out? I thought I'd share the process that I have used successfully. This article is a companion to writing PCs for character-provided events.

1. What would be interesting for the PCs to do? What situations do you want to see them in? Is there some type of encounter that one or more of the PCs would excel in, or have interesting difficulty with? Is there a particular type of encounter you are craving? Make a list of the "coolest" encounters you can think of.
2. Climax. What will be the climax of this event? Will it be a battle, a revelation, a confrontation, a sneak-in-and-blow-it-up, or what? Think about how to incorporate the PCs into a scene like this - what elements can you include that the PCs will be able to use their special abilities with, activate their phobias, etc.? Describe the climax.
3. Introduction. Where are the PCs when this all starts? I believe that the first encounter should give the PCs a bit of time to role-play, but should also give them plenty to talk about. If the introduction is a major event, then they can talk about it. Sometimes starting with a battle is good, sometimes starting with a chase it good. Just saying "you are all in a room - go!" is not good. The PCs need events to discuss.
4. Event Filtering. Now you have the Beginning, End, and a bunch of possibilities for the middle. Based on your first and last encounters, pick your favorites from the first step. For a 4-hour slot, you need 3 hours and a little material. This usually works out to 6-10 encounters. It's a good idea to have a balance of trick/trap encounters, negotiation encounters, combat encounters, and investigation. You also need some down time for the PCs to chit-chat. Add a few, and remove a few to get to a good number.
5. Event Chain. Chain the Events you picked into a logical order. If the event is non-linear, that is, the PCs could play the events in any order, then put the parallel ones at the same level in the chain.
6. Pacing. Think about the pacing of the event. If you start out with a battle, do you immediately crash into another? Do you need some downtime in between? The main thing is to keep people interested. Too much downtime is worse than none. Look at rearranging things to keep the players interested.
7. Plot check. Look at your overall plot. Do the encounters you have fit the plot? Can they be made to? Each encounter in a convention scenario should advance the plot or be a major piece of character development.
8. Something cool for each PC. Does each PC have something cool that they can do during the course of this adventure? Make sure they do! You may have to adjust the encounters, or the PCs.
9. Connections. Time to link each encounter to the next. Look at the entry and exit of each encounter and make sure that it is clear how each encounter feeds into the next.
10. Encounter Level. Make sure that each encounter is of appropriate challenge to the PCs. You need to look at the "relative encounter level" as well as if the PCs have just come from a big battle that is at or above their ability, a relatively weak encounter may be a lot more of a challenge - sometimes this can be fun. After getting their butts kicked by the trolls, the kobolds seem like a lot more of a threat.
11. Add another Layer. Take a look at each encounter, and see what you can do to add another layer of interest to it. For example, if it is a combat encounter, how can you tweak the environment to affect the combat (multiple height levels, cover, mist, storm, etc.) You can often make an encounter a lot more interesting just by mixing up the "standard" stuff a little. (Thanks to Todd Landrum for inspiration on this step).
12. Playtest. If you can. If not, have at least one other person try and make sense of what you have.
13. Refine. Go back through and tweak everything. Often, I have to edit out encounters, reduce the number of monsters in an encounter, add more clues to connect encounters, etc.