My all time favorite Manga is Berserk. In it, the main character, Gatsu(Guts), is given a hell hound headed set of cursed platemail. The armor turns off the victim's sense of pain, allowing the person wearing it to push themselves past their mortal limits. Below is an altered version I'll be introducing into my campaign to try to get the fighter to put the War back in warrior(rather than having the wizard keep taking point).
Cursed Armor of the Berserker
Black platemail armor, with a savage looking Hell Hound headed helm. The armor physically radiates an aura of rage, detectable by any intelligent being. Creatures under 1 HD must make a Save vs. Paralyzation or react as if subject to a fear spell to the creature wearing this armor. All social rolls made while wearing this armor are at a -4 penalty, except for Intimidation, which are made at a +2 bonus.
When first putting on the armor, the character must make a save vs. Death Magic, or permanently lose a point of Constitution as the armor consumes some of the users life force. The process is very painful, and the character is unable to take any action for 1d6 rounds.
When the character is first subject to an attack, whether it succeeds or not, the player must make a save vs. spell or be subject to a berserker rage. The wearer may willingly fail the roll, but if he passes, he must make another save every time he is hit.
When the character enters a berserker rage, the DM should take note of the character's current hp. From this point onward, the player does not know the current health of his character. The character automatically gains a +1 bonus to attack, and +2 to damage.
Every time a blow lands against the wearer, the wearer gains a +1 cumulative bonus to attack and damage(stacks with the initial bonus), this can occur no more than 1/round. This bonus continues to stack until combat is over. On rounds where the character is not harmed by attacks, the armor itself causes 1 hp of dmg.
While in this state of berserker rage, the wearer is immune to pain, fear, or charms. He also does not drop at 0 hp, but continues fighting until he reaches -10 hp(and falls over dead) or all targets are dead.
The wearer attacks the closest target(friend or foe), running through walls of fire if necessary to reach his target. The primary target is whoever struck the first blow against the wearer.
The armor may only be removed in one of Four ways. The first option is that the wearer is killed. Usually however, by this point the character has suffered such extensive damage that there is only a 25% chance that any sort of raise dead/resurrection spell would work. Reincarnate works normally however. The second option is a Wish/Miracle spell, which allows the character to remove the armor normally. Putting the armor back on however, would result in the character being under the curse again, taking another point of Con dmg. The third option is for the character to receive a Remove Curse Spell. This spell allows the character to make a new Save vs. Death magic. If passed, the armor may be removed. If the save fails, all further saves to remove the armor are made at a cumulative -1 penalty.The last option involves a quest in which the wearer must face his own inner beast. If the wearer wins, the armor may be removed and worn without any penalties, and the wearer will only be subject to berserker rage when he desires to enter it.