With Berserker Strength and Ettercap Berserker, whenever Brianna the Barbarian is in a particular range of hp, she ends up in an infinite rage/unrage loop-- low HP triggers Berserker Strength, which grants +6 con due to Ettercap Berserker, raising her HP high enough to deactivate Berserker Strength, causing her to lose the +6 con and fall below the threshold for Berserker Strength, causing Berserker Strength to activate, and so on and so on.

Because Berserker Strength is instantaneous, Brianna is constantly in a paradoxical cycle of rage.

Unfortunately, all the fun things that trigger when a Barbarian enters rage are Pathfinder material, not 3.5 material (AFAIK).

Also, for Cursed Sword shenanigans, I recommend using a shuriken-- it's its own ammunition, and unambiguously a "weapon".