Some people just don't like mathematical riddles (it is mathematical, right?) but prefer other kinds.

Quote Originally Posted by veti View Post
As a rule, I don't like puzzles. With few exceptions, they usually boil down to "read the DM's mind". And with even fewer exceptions, they just don't make narrative sense. Why would anyone, anywhere, ever, want to make "opening a door" contingent on the ability to solve a puzzle? Really, the only plausible explanation is an eccentric wizard playing silly beggars just for the sake of it, and the phrase "colossal waste of time" floats irresistibly across my mind.

Instead of puzzles, I suggest practical challenges. How to steal a sword from the lord's trophy room without anyone noticing it's missing. How to rescue the extremely fragile hostages from the trigger happy bandits. How to find that bard who's been making out with the lord's son, and what to do with him when we do. Something meaningful.
Formal riddles can make sense in very specific circumstances, e. g. as a test of wisdom (I will make sure that whoever finds the ring of power will be wise enough to use it well) or if the riddle is tailored to a very specific group like your guild (e. g. players have to know some secrets that are usually not available) so that everyone in need may pass, or in a death maze that serves the amusement of the mad wizard.

But informal puzzles can be a lot of fun, too. (list of examples incoming)
An easy way to do so is too convey some seemingly unimportant bit of information in the beginning and make it important towards the end.
Then you have murder mysteries where players have to find and combine clues to reduce the number of suspects.
Another kind of riddles are parallels: give the players a solution for a problem (e. g. the recipe for a potion), and later on they encouter a similar problem and have to solve it in a similar but different way (e. g. find substitues for the ingredients: a different herb, hair from a bold man...).
Remember and combine: Give the players some information that might be valuable, but for them to get a reward they have to use it right (e. g. they find a secret plan, but they have to find out who is most interested in it)
Open situation: Just prepare a situation, e. g. a heist with a twist, and see how well the players prepare. You can split it up in minor riddles, too.