So, Telecanter comes up with this neat, simple flowchart thingy for dealing with locks and mechanisms.
Zak adds his own take on the system.
I have but three things to add. One is an observation that with a lock, you succeed by getting it to work and fail by jamming it. With a trap, you succeed by jamming it and fail by getting it to work. So, you can use the same procedures for the two, but with different desirable outcomes.
Two is a variation. Roll on the list of 36 text-adventure-style action words from the "black die 1" column of Table D in my Endless Bag of Tricks pdf. Do this once for each of the action words you're using to solve the mechanism. It's then on you to come up with a trap/trick/lock description that uses them all. I just rolled up "Move," "Turn," "Sit on," and "Push" which suggests a nasty-looking rotating door with a built-in seat.
Three: could you use an actual puzzle in-game? Having played a fair number of the Big Fish hidden object computer games, I am excruciatingly familiar with the kind of old mansion whose exploration requires completing Towers of Hanoi, 15/16 slider puzzles, pipelaying games, and the like. I am pleased to say that the recent Mansions of Madness board game from Fantasy Flight includes this kind of mini-puzzle in a way that doesn't feel overly forced or corny. At least after one play. So perhaps that can be useful, every once in a while.
Oh yeah, and speaking of mechanisms, this, if you ever wondered what a DC 35 lock looked like.
