Whirling Frenzy (D&D Barbarian variant)
|Unofficial rules compendium
Unearthed Arcana, page 67
A barbarian with this variant form of rage doesnt gain the normal bonuses when he enters a rage. Instead, when a barbarian with whirling frenzy enters a rage, he temporarily gains a +4 bonus to Strength and a +2 dodge bonus to Armor Class and on Reflex saves. While in a whirling frenzy, the barbarian may make one extra attack in a round at his highest base attack bonus, but this attack takes a 2 penalty, as does each other attack made that round. This penalty applies for 1 round, so it also affects attacks of opportunity the barbarian might make before his next action. Whirling frenzy is otherwise identical to the standard barbarian rage in all other ways.
At 11th level (when a standard barbarian gains greater rage), the Strength bonus increases to +6, and the dodge bonus to Armor Class and on Reflex saves increases to +3.
At 20th level (when a standard barbarian gains mighty rage), the Strength bonus increases to +8, and the dodge bonus to Armor Class and on Reflex saves increases to +4. A barbarian using this variant doesnt gain indomitable will at 14th level. Instead, he gains evasion, but only while in a whirling frenzy.
A character cant use whirling frenzy at the same time that he uses any other form of rage (or similar ability).