The Storm of Insurrection
Each round, characters receive combat opportunities, which allow you to perform special actions during your initiative or outside of your initiative. Combat Opportunities will enable you to take swift or immediate actions, as well as perform special defensive or offensive moves.
A character receives 1 combat opportunity plus an additional combat opportunity per 5 levels.
Most swift or immediate actions cost 1 combat opportunity (I have not analyzed all the possibilities here). Most swift and (and probably many) immediate actions cannot be performed more than once in a round (even if you have leftover combat opportunities.) Immediate actions count against the following round or the current round, depending on how many combat opportunities you have. (You can also spend the current round plus the following round to conduct an action that requires multiple points.)