Dragon Age 2 seems to have more awesome and easy-to-execute exploitable glitches than any game in a long time. It almost seem deliberate, which would be a really awesome move on Bioware's part. This video will teach you how to use a really simple inventory glitch to max out any character's armor stat at 100% in less than a minute. You will be almost indestructible, and you can stop whenever you want if you just want a more reasonable boost.
From the Creator:
This can only be done using a character that is able to equip a shield.
1. Player must own a shield for the character they want to boost the armor for.
2. Pause the game and go into the inventory menu.
3. Select the character you want to boost.
4. Equip and unequip shield over and over.