Help creating a puzzle

[parinho7]

I am the DM and i need help creating a puzzle.
The players will go to an ancient city now in ruins and there will be a secret door. It is now used by a secret organization for their meetings and rituals. I want a riddle/puzzle for opening the secret door.
Quick please tomorrow we are playing the session
Thanks

[Gilladian]

What if the door has some sort of changeable lock (such as a set of 5 wheels, each with 6-8 letters and/or numbers or symbols, even, engraved on it); the leader of the cult comes along each week and resets the code for that week, and then each member is given the new code word via some sort of signal. Perhaps an object is left in the room where the secret door is located. That object gives the knowledgeable person a clue as to what the code word is.

So the PCs enter the old basement under the warehouse, find the secret door behind the wine-barrels, and it is locked with a barrel-lock. They have to input the proper 6 letter combination to open it. Sitting forlornly on a shelf nearby is a single bottle of wine, unbroken and unopened (and to the careful observer, remarkably dust-free). The wine label bears pictures of a particular flower. Entering the word "daisy" on the barrel-lock opens the door.

[aco175]

I guess it would depend on your group. I would have to run a search on Google because my group knows the riddles I know, but with my kids I can use the more simple ones I know from books and movies.

One of my favorites;
He who makes me, does not use me. He who buys me, does not want me. He who uses me, does not see me. What am I?


Answer: a coffin

You can also have a wordplay riddle with a clue that can be tied in with a skill check. One of my Necromancer modules has you place a silver ring in the middle of stone. Characters placing the silver in the middle of the table, misses the part that the middle of STONE is the letter O, which the skill check can clue something about that.