Has anyone got any interesting house rules for when someone makes that perfect 01 roll on a skill test?

I know there are already degrees of success but the fact that a 01 is such a rare roll perhaps it needs something more than that.

I was considering giving the the person that rolled the 01 a permanant +1 to the skill in question if they already had the skill trained. Something to signify that they had a moment of clarity and now actually understand the skill a little better.

I know it isn't likely to come up a lot but I think it could help to get the players excited when it does.

Usually they let me know exactly what they expect should happen, and then I sigh and get all upset before reluctantly revealing plot details that I wanted them to have, and then they advance the plot in exactly the way I had hoped.

For combat it usually means "Attack cannot be dodged or parried".

In combat I say that the hit bypasses armor, having hit just that sweet spot. There was once an interesting occurrence when an arch-militant managed to score a 01 to hit with a Man-Portable Lascannon - who knew that Chaos Space Marine eye lenses were so fragile?

For skill checks, I generally just say that the results are suitably awesome with cinematic description, and with lore checks I tell them everything their character could possibly know.

I usually have a 01 result in a positive advantage (such as bypassing armor or having that new boltgun you purchased have a clip of rare ammo in it). On the same token, a 00 is painful experience. Of course, my players are unwilling to let a 00 stand even on the most innocuous of rolls. Chatting up that lady at the bar, unfortunately she is a Chaos psyker looking for a sacrifice...

We use the d20 standard rule of there being a 1 in 20 chance of a great or terrible thing happening - a critical if you will. This means any roll of 01 - 05 succeeds and any roll of 96-00 fails. This gives a chance for even a lowly mook to score a blow against powerful enemies, or an average crewman to suddenly have some insight and pull off a task nobody expected them to. Similarly even the most potent enemy can occasionally stumble or forget something.

For degrees of success we have variably ruled a 'crit' roll as being the maximum possible effect in the given situation (ie if a weapon has the accurate trait, then you rolled well enough to fully activate it).

Technically speaking you're supposed to confirm the critical in D&D, so it's generally closer to 1 in 400, leaving alone the fact that skill checks don't crit by RAW.

Technically speaking you're supposed to confirm the critical in D&D, so it's generally closer to 1 in 400, leaving alone the fact that skill checks don't crit by RAW.

Well "confirming" a crit means you hit on a second attack roll, and unless you're a wizard with a non-proficient weapon the odds will be quite a bit better than 1 in 400. A combat-focused character can usually hit someone's AC on a roll of 11+, so that'll be 1 in 40, meaning they'll crit two and a half times in combat during a session to equal the one you'll get in RT.