I haven't much used action points as yet, as I am still considering when and how they can and should be used, gained, lost, etc.
One idea I've been playing with trying is the idea of Luck points. In effect, if the character is about to make a check where they cannot succeed with 'taking 10' and there is a penalty for failure - whether this be a skill check, a save, an attack, etc, they could choose to put aside a point or more (I've not yet decided whether more than one can be put aside at a time.), thus worsening their chances of success. But later, when faced with *any* (even if they have no penalty for failure or can take a ten for success) skill check, attack, save, etc, they can then use that luck point to have a better chance of success.
In the long run, they would, in effect, make their own luck - by first taking a chance at bad luck occurring.
As an example, a character is about to jump a pit and needs to roll at least a 12 to succeed. They could choose to increase the DC by +1, requiring a 13 to succeed at the jump.
Later, when poisoned perhaps, they need to make a fort save. They add the +1 luck point they gained earlier to their roll, in effect reducing the DC by 1.
Or perhaps they are making a perform check to get a coin or two so as to buy a room at an inn, and they want to increase their result - and thus how much they will get from the perform check.
Or perhaps they are making an attack, requiring an 8 to hit, and wish to have a little extra help in making the hit.
The only problem that comes to mind with this system is that it is quite arguable as to whether losing a point from a skill check should count equal to losing / gaining a point in a save or attack. Does increasing the chance of failing a reflex save by 1 equal gaining a +1 to a later attack? What about a +1 to a knowledge check or a Spot check?
Anyway, this is just an idea I've been playing with for a while. I may try it out the next time the group starts a new quest. (It would be odd adding a new rule in the middle of a current quest, I think.)