Advice on Compels

Essentially, a Compel is where an Aspect is invoked on a character to forego a roll in place of a dramatic, interesting plot effect.

Here are some good links I've found on the subject of Compels:

Fate Compels in a Nutshell

How Fate games could go wrong and how to prevent that

The Formula :

1. Something relevant to aspect X happens. 2. The player chooses to respond with Y. 3. Z happens as a result.*

* = Z is something complicated and/or horrible, and is not bound by the application of other game rules (like skill rolls, etc.)

The Compel Templates :

• Event-based: You have ____ aspect and are in ____ situation, so it makes sense that, unfortunately, ____ would happen to you. Damn your luck. • Decision-based: You have ____ aspect in ____ situation, so it makes sense that you’d decide to ____. This goes wrong when ____ happens.

A really good explanation via example:
 * 1) Remember that in Fate, the  player  is always an informed participant, even when the  character isn't. The gap between player and character knowledge is  much  bigger in Fate.

Situation: A hostage is tied to a chair. There is a trap which incinerates the room if anyone touches the hostage.

D&D answer : Tell the players nothing. Make hidden Perception checks. If anyone explicitly searches, make Search checks. Lie unless the players succeed at these checks.

Fate answer : Tell the players immediately that there's a trap. Let them make rolls and use aspects freely to see if the  characters  spot it. If one of the players has a "reckless" or "rescuer" aspect, compel it - offering a fate point if their character runs in carelessly and sets the trap off. Make the players  partners  in decisions that hurt their characters.