The other was a mysterious Delta blogpost on climbing that seems to have disappeared. Basically, just a conversion of the thief climbing rules from percentile to d6, expanded to apply to all classes (but giving thieves an edge.) It's similar to what I would do, except there's a definite shift in focus and interpretation: under those rules, you roll to see whether the climb is successful.
My approach is not to roll for success, but to roll for unintended consequences. I've hinted at this approach before, especially when talking about "1 in 6" chances: if you can normally do something, but there's a chance something can go wrong, that base chance is 1 in 6; if you can't normally do something, but there's still a chance of succeeding by pure luck, that base chance is 1 in 6. Of course, I modify this a little by rolling two dice and looking for doubles, but it amounts to the same thing.
So, for climbing, if there's a chance of a rope breaking or a stone slipping, then I roll for a 1 in 6 chance. Characters who start to fall can attempt to recover (saving roll,) with thieves getting a bonus based on level and other classes getting bonuses based on what they do to try to save themselves. Most other things are handled the same way:
- If a character jumps a pit, either the jump is impossible or easy (no roll in either case,) or there's a 1 in 6 chance of falling, with a possible save to catch the edge of the pit.
- If a character crosses a rickety, decaying rope bridge, there's a 1 in 6 chance it breaks, with a possible save to grab one of the ropes and climb to safety.
- If a character crosses a frozen river, there's a 1 in 6 chance the ice breaks, with a possible save to jump at the last minute.