Here is an altered version of the action point rules found in products such as d20 Modern and the Eberron campaign setting, another of the variants I've been creating for the 7th Circle. If you wish to include them in a game that does not normally feature action points, I suggest having the number of action points player have at each level equal 5+half their character level.
Character Level - Action Point Dice Rolled - Maximum Points Per Turn
1st–4th - 1d6 - 1
5th–8th - 2d4 - 2
9th–12th - 2d6 - 2
13th-16th - 4d4 - 3
17th-20th - 3d6 - 3
Action points provide characters with the means to affect game play in significant ways. A character always has a limited amount of action points, but while the character replenishes this supply with every new level he or she attains, any unspent points from the previous level are lost. A character can spend 1 action point to do one of the following things:
* Add your action point dice to a single d20 roll used to make an attack, a skill check, an ability check, a level check, or a saving throw. A character can declare this use of an action point after the d20 roll is made, but only before the GM reveals the result of that roll (whether the attack or check or saving throw succeeded or failed).
* Use a class feature or special bonus ability during your turn for which the expenditure of 1 action point is required.
* Make a check with a trained-only skill as though it could be used untrained.
* For one round, gain the benefit of a feat for which you meet all the prerequisites.
* As an immediate action, gain your character level plus your action point dice in temporary hit points. These hit points last for one round per level.
* Add action point dice to the amount of hit points restored through natural healing, multiplying the number of dice rolled by the number of hit points restored per character level (so double the normal number of dice for a full day of rest and triple for a day of long-term medical care).
* With GM approval, use an ability in a way that is theoretically possible and dramatically appropriate but not normally possible under the given rules.
At first level, a character can spend a total of 1 action point per turn and adds 1d6 to the result when spending an action point in a way that adds action point dice to a result. At higher levels characters may spend additional action points (though not to add additional action point dice to the same result) and add more d6es to the result when adding action point dice, as listed on the table below.