Nature: Game mechanics.
.
Basics
Received: 5 + 1/2 current level (rounded down) + Charisma bonus (if any)
Gaining: Score resets to max upon gaining a new class level. Unspent points are effectively lost.
Using: Max 1 per turn, unless special ability or Feat allows more
See also: Action Point Feats
.
Possible Benefits
Boost a d20 roll: Add +1d6 to the result. At 8th lvl this is +2d6, and at 15th it's +3d6.
Activate Class Ability: Get 1 more use of class ability than its limit per day allows.
Emulate Feat: Act as if had a Feat you don't, if you meet its Prerequisites, until your next action.
Boost Feat: Increase benefit of a feat, often roughly doubles it. Individual details per Feat.
Extra Attack: When doing a full attack action, get +1 attack at highest attack bonus.
Extra Defense: Get double the bonus for fighting defensively.
Spell Recall: Don't actually expend spell's energy as it is cast, so can use again later on.
Survive: Become stable when dying.
Be Awesome: Perform heroic and impressive deeds that normally wouldn't be allowed,
or spend the point to make other actions simply look more impressive and epic.