Jack Daniel
Legend
I use them in my D&D campaign. It helps facillitate two important factors in my games -- the first is that my world is a swashbuckly setting, and action points cater to the sort of stupid stunts that heroes are supposed to attempt (likewise with the Heroic Surge feat). Second, it opened up a fabulous mechanic for eliminating multiclass XP penalties while retaining favored classes.
In d20 modern, characters need lots of action points, in part for the extra dice and in part to use certain class talents. So, of course, characters get 5, 6, or 7 + one-half their character level in action points at every level. That's not really neccessary in D&D, given that the classes are supposed to be balanced before hand and action points don't activate any class features, so I award 2, 3 or 4 action points per level, based not on the specific class, but on the class type. 2 points for a basic class, 3 for a prestige class, and 4 points for a racially favored basic class. Giving out more points for advancing in a favored class and eliminating XP penalties altogether helps cater to elven wizards and dwarven fighters, and often eliminates characters with one or two levels in their favored class (something that always bothered me about the core system).
In d20 modern, characters need lots of action points, in part for the extra dice and in part to use certain class talents. So, of course, characters get 5, 6, or 7 + one-half their character level in action points at every level. That's not really neccessary in D&D, given that the classes are supposed to be balanced before hand and action points don't activate any class features, so I award 2, 3 or 4 action points per level, based not on the specific class, but on the class type. 2 points for a basic class, 3 for a prestige class, and 4 points for a racially favored basic class. Giving out more points for advancing in a favored class and eliminating XP penalties altogether helps cater to elven wizards and dwarven fighters, and often eliminates characters with one or two levels in their favored class (something that always bothered me about the core system).