Over at the B/X Blackrazor blog an interesting post on shields in D&D reminded me of a little house rule of mine that pops up from time to time: my weapon breakage and fumble rules.
I do use a "fumble rule" on a d20 hit roll of 1 a combatant is done attacking no matter how many attacks a round they get and I judge if the situation could warrant an additional effect. Usually rolling a d6 as so
1 Fall Prone
2-3 Lose Weapon
4-6 Damage weapon
A weapon gets a save vs damage equal to the characters chance to save vs death. Magical weapons save at least as well as 9th level fighters if one is of lower level, the bonus of the magical weapon is included.
If a weapon is damaged it is downgraded by -1 in chances to hit, damage (and save). Magical weapons can still strike foes requiring magic to harm until they are damaged past their original plus as a negative (for example: +1 weapons stop being magical when reduced to -2)
A weapon is destroyed if it's negative exceeds 1/2 the normal damage roll. (daggers are ruined at -3, swords at -5)
Some weapons crafted of inferior or fragile materials can be damaged when the hit roll is a 20, all that stress on the weapon is bad indeed. Save as above.
Oh yeah shields, if you haven't read blackrazor's post go do so it raises some good points, I don't totally agree across the board but it's well thought out and reasonable.