A 1 on an attack role is critical failure you roll again if you hit your target nothing happens if you miss depending by how much you drop your weapon, lose your turn, break your weapon if it is non magical and non masterwork.
4. Characters die at -10 minus their constitution modifier (instead of -10).
My house rule on this is that if you roll a 1 you roll to hit your target again. If the second roll would have hit the target then you simply miss. If your second roll would have also missed then you give up an AoO.
Sort of my version of a reverse critical hit. I couldn't come up with something appropriate for ranged characters though. Maybe it could be that your attack hits an ally instead?
Olaf the Stout
For 3.5e:
For almost all campaigns, I use a "no prestige classes" rule.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.