I was thinking about pit traps in dungeons a while back. Apparently (haven't looked at my pdfs, just read some stuff on Dragonsfoot about the subject), OD&D doesn't go into specifics of the damage done by pit traps--there's some rules for falling damage in there somewhere, but not in the pit trap section. That's where the standard 1d6 per 10' fallen rule comes from.
Well, for pit traps in a megadungeon, or at least one with multiple levels designed to get harder as one progresses, I've had a simple idea.
A pit trap does 1d6 damage for each level of the dungeon you happen to be on. So if you're on the 1st level, that pit trap is only 10' deep and you take 1d6 if you fall in. If you're on the 3rd level, it's 30' deep and you take 3d6. If you're on the 6th level, better hope you've got lots of hit points and your buddies up top have at least two lengths of rope! You've just taken 6d6 and have a 60' climb ahead of you!
I like this, as it means I can simply make a note on the map of where a pit trap is, and don't have to write down how deep it is. The only extra notes I'd need is if there were spikes, it fills with water or some other substance, a monster was at the bottom, or something like that.