Puzzles and Riddles

D and D puzzle, riddle ideas:
Hourglass
The party enters a room and gets sealed in. An hourglass lowers from the ceiling, behind some impenetrable barrier. It has two minutes worth of sand, and it was suggested you bring an egg timer to enforce this on your players IRL. There's also a red button that, when pressed, resets the timer to the original two minutes. It also deals one damage (or some other trivial amount) to whoever pushes it. The room unlocks when the timer expires.

Match the Mirror
The reflection shown in the mirror in this room isn't right. There's an extra object, or an object missing (or even an extra person!). The players need to find the missing object, and place it in the right spot in the mirror to pass.

Treasure Trick
A chest in the room is empty. There is a mirror on the wall, that shows everything to be normal, except that the chest contains treasures and magic items. As the party watches in the mirror, and old man comes and removes an item from the mirror-chest and leaves again. He does this repeatedly until the chest is empty, at which time he points at the party and laughs hysterically. If the mirror is tilted on its side, the remaining treasure will spill out of the chest upon the floor, both in the mirror and in reality. If the old man is present when this happens, he will also fall down and appear in the room, where he will answer one question truthfully (with a cryptic riddle of course)before cackling and disappearing in a puff of smoke.

Riddles:
What question can you ask all day and get a different correct answer every time? Answer: “What time is it?”
What falls every day but never breaks? Answer: “Night.”
What are the next 3 letters after “O, T, T, F, F, S, S”? Answer: E, N, T. The first seven letters stand for: “one,” “two,” “three,” “four,” “five,” “six,” “seven.”

Some I have found on other websites and like the look of, to get the ball rolling, anyone else got any others?

Did a fun one with my group a few days ago.  In order to access the top of a wizards tower they needed to pass three tests.  This was one of them...

A teleportation circle transported the group into a spherical chamber with runes all over the inner surface.  The floor was also pockmarked with small gaps (perfect handholds for climbing).  A small pixie-like creature popped into existence and activated a rune at the top of the sphere which glowed blue.  A rune at the bottom of the sphere lit up and glowed red.  None of the characters could speak sylvan so the pixie mimed that the sphere at the top of the sphere needed to reach the bottom.  As the characters moved throughout the room, it rolled like a giant hamsterball.  The blue rune moved with the sphere, but the red rune moved along the inside of the sphere to stay at the bottom.  The players were able to move throughout the sphere and maneuver the first rune to the bottom without issue, and once the blue rune came in contact with the red one, it flashed and disappeared.  However the pixie activated another, and this time holes opened in the sphere threatening to dump the players into the pit below.  After the second rune was gone, giant spiders came through the holes and started using web to restrain players in place (if they didn't remove the web fast enough the spiders would move to hang the players upside down from the inside of the sphere).  After the third rune was gone the Pixie got involved and used spells to teleport the players around the sphere and to change their weight (see mechanics below).  If the players were able to clear the third rune, they were teleported back to the tower and the staircase to the next floor was opened.

Mechanics:  Creature weight Small=1, Med=2, Large=3

Pixie spells- Gravity: Doubles targets weight until the start of the pixie's next turn.  
                  Feather light: Reduces targets weight by 1 until the start of the pixie's next turn.

The room was drawn on a battlemat (squares) represented as  2 sets of 3 concentric rings.  The set on the left represented the bottom of the sphere.  The innermost ring was the bottom of the sphere and had a weight multiplier of x1.  The ring outside that began the slope up the inside of the sphere.  Movement across this ring was considered rough terrain and creatures in this area had a x2 multiplier for their weight.  The outermost ring was the area of the sphere that was nearing vertical.  A Acrobatics chack vs. DC 12 was needed to move ore the player fell prone and slid back into the middle ring (dangerous if there are holes in the sphere).  Creatures in the outer circle had a x3 multiplier to their weight.  After that, the players would need to make Athletics (DC 14) checks to transfer to the right-hand set of rings, which represented the Upper hemisphere, where the creatures were hanging from the ceiling. The rings on the right-hand side had the same weight multipliers as the rings in the left hand sphere.  On initiative count 20 each round the sphere would roll in a direction and speed based on where the weight was distributed across it's surface.  The spiders and pixie would do anything necessary and work together to throw off the direction the sphere was rolling to prevent the rune from reaching the bottom.  A favorite tactic of mine was to have the spiders (large creatures) move to the x3 multiplier zone and then have the pixie use magic to double their weight.  Unless the players found a way to counteract the weight, the spider would count for 18 weight for that round, likely rolling the sphere in the wrong direction.

I have trouble with puzzles and riddles because some players don't mind the player being the one who did the solving (I'm in this camp) but other players (understandably) want their character's ability and knowledge to be the primary force in solving the puzzle. To appease both sides, I usually design the puzzle with specific insights, shortcuts, and clues that can be obtained by dice roll on a character's knowledge, ability, or intelligence.\

That said, I love the hour glass one for the simple cruelty and the treasure trick I am probably going to have to steal some time.

For my own contribution, one of my favorites was a set of three scrolls hanging on the wall with the upper portion of a symbol known to the players etched in the stone above them. As the scrolls are unrolled, ink draws different portions of the symbol on them, but out of order. The scrolls can be retracted by pulling them to floor level. On the back end, the parts of the symbol are stored in a stack-like database formation (last in first out) and the key is to use the 3 stacks you control (the scrolls) to sort the parts and recreate the symbol (video demo and download here if you want to use it).

I also like to use items as puzzles, since they can carry them around and do them at their leisure. In my last session, though, this didn't turn out so leisurely. One player found a ring she kept secret from the others (who were distracted by a broken mirror nearby, which they took). When the opportunity arose, she put the ring on to find it removed her ability to hear and made others invisible to her (it had also made her invisible and silent). She couldn't remove the ring, but she followed the trail the other characters were leaving by not closing doors behind them (she has tracking, so that would have worked too). The crunch to fix the problem came when lunch came along and she realized she wasn't carrying any of the party's food and she couldn't touch the food the other characters were enjoying. She eventually managed to get the attention of the rest of the party using a magic item to make some light they could see and after praying to a god of knowledge they had a vision that implied the broken mirror was important. Upon taking the mirror out, the ring-wearing player was able to see the others in the reflection and even touch them as long as she was watching them in the reflection. They repaired the mirror and set it down, she was able to pick it up. Eventually she discovered she could reach into the mirror and remove the ring from her reflection. They now inspected the ring more closely and found the words "which is the reflection and which is real when neither makes a sound" etched inside the band. Having solved it, it may be a powerful tool for them.

Not to go on too long, but I'm fond of giving them a picture and some knowledge checks that will give clues as to how pieces of the picture need to be changed to solve the puzzle. (Bomp and Bomp)

A puzzle that is not a puzzle, but by playing off a troupe to becomes a puzzle maybe.
The players come across a large metal door. The door is decorated with motifs of demons. "Sacrifice yourself" is spelled out on the door in bold red letters. A metal demon holds forth a bowl, in this bowl is a small hole. the is a hand impression in the door with blades that would puncture the palm.

"Clearly you cut yourself and drip the blood into the bowl to unlock the door."
The trick: If you use door to cut yourself you are injected with a poison. Putting any liquid in the bowl (blood or not)does nothing. the door pulls open. that's it. you can simply just pull it open... I haven't tested this yet. i can't wait to.