There was a lengthy thread on this very topic.
Basically my logic in interpretation of the rules is this. . .
Per the RAW all of your movement is resolved on your turn in the initiative order.
Per the d20srd, if you are Bull Rushed, you are moved during the attacker's turn and you provoke AoO as a result. I don't see how one can come to a reading that would resolve the attacker's movements on the attacker's turn and the defender's movements on the defender's turn. That would lead to a situation where for who knows how many intervening turns, the Attacker was actually past the Defender...then suddenly the defender blinks to the Defender's position as a result of the Bull Rush?
Now i'll throw my wooden shoe in the machine...what happens if it's a 30' fall and there is a creature who is waiting next to the square in which you'll fall, and the creature's turn comes up before yours? Do you just hang in mid-air until it's your turn...out of the creature's reach?
The trap (which is much harder than being pushed but substitute "attacker" here) makes its attack on it's turn (let's say it was a surprise).
What do you mean by "is much harder"? Do mean harder to resolve?
So the surprise attack is successful, you now will fall on your turn (when all of your movement is resolved).
So an object which is knocked over by a creature would never fall because it does not have a turn?
I note that my interpretation still allows for all of the acitons to work pretty much as written and essentially requires no house-rules (or further brain wracking on how to handle things).
I think there are two things at work here. The first is that WotC wants to allow people to "react" to various situations without that incurring some Action tax and preventing the character from taking a Full Round action on that character's regular turn. Which is why they categorize things that are "no action" or "nonaction" activities: You can do these things and still take your Full Round action.
The second problem is making sure these things are not construed in a way that suggests that the character "had a chance to act before his regular turn." This is crucial to preserving the FF status. With an Immediate Action, they just flat out said, you can't do this FF'd. Problem solved. I doubt anyone considered the impact to Feather Fall and being FF'd when you get knocked off a cliff (but you never know). It's also a safe bet they overlooked the free action Speak option...but there's little doubt they do not intend this to remove FF'd even though, RAW, would technically allow it. Like Celebrim would argues...if the literal meaning of the rules seems self contradictory...then you are forced to look for an alternative interpretation that gives meaning to the words. I believe this is called "construction" with respect to contract law.
I'm not done twisting your corpus collosum in a knot irdeg. Let's say you fall off a 10' ledge while being FF'd, but you make your Reflex save and take no damage. Are you still FF'd when other creatures come over to attack you...before you've had your turn?
