El Mahdi
Muad'Dib of the Anauroch
Critical fumble house rules are terrible. They favor only sadistic DMs and low level characters.
[MENTION=31734]Infiniti2000[/MENTION]
I disagree. But...
...To me (and my group) D&D is about heroic fantasy. Its bad enough when you miss, but to make me stab my buddy or accidentally toss my weapon across the map? That's not very heroic. I'm not trying to play clumsy, real-world me. I'm Torro! Human fighter and ass-kicker who may miss, but is competent enough to hold on to his axe!
If I want that kind of "realism?" I play something else.
[MENTION=65116]Chris Knapp[/MENTION]
I have to 100% agree with this. Nobody likes their character looking stupid. As a DM, I don't want to, nor do I, seek to make a character look stupid (however, a player making their own character look stupid is an entirely other matter, and probably their own fault

What I do instead on a natural 1, is that there's a small chance (5%-10%) that they've broken their weapon (unless magical, or an heirloom/named weapon - which I give straight plot immunity). If they don't break their weapon, then they've simply overextended themself and made themselves more vulnarable than normal (providing a -1 to -3 penalty to defense for the next attack from that opponent - and that opponent only).
Even in heroic fantasy fiction, there's the precedent for the hero's weapon breaking, or the enemy getting a good shot in on them due to a mistake (it would still be just a normal attack, at a slight defense penalty, against only one opponent - not a critical or an automatic hit and no extra penalty against multiple attackers).
It kind of models fights like Kevin Costner and Alan Rickman (Robin Hood and the Sheriff of Notingham). The Sheriff, wielding Robins' Fathers' sword, breaks the sword that Robin is wielding (a simple, mundane sword) and gets in a "hit" that cuts Robins chin - giving him a scar to which the sheriff says: "Now we're even!".
It's a simple houserule that adds some extra dread to a fumble, without significantly altering the balance of the game, and provides for extra dramatic opportunities. (In other words, no sadism, only drama.
