Need challenge room ideas

Building a "dungeon" in the sense that it's a linear set of rooms leading to the final room with treasure. My player group is diverse in terms of age (youngest player is 13, oldest is 45), so nothing super complex that would rule out the kid being able to solve things. Definitely going to throw the "room that locks down when button in the center of the room is pressed with a series of countdown crystals over the exit and pressing the button resets the countdown" at them, cuz I will enjoy them trying to solve the puzzle that is really just a countdown till the doors open. Need other ideas for rooms that are not just "kill these monsters to continue"