As we end the year, I will take this post to remind everyone to not overlook simple traps. Overworked, deadly, complex and devious traps are fun, but they can't be everywhere, and, in my opinion, should not be hard to find. Nothing takes the sails out of a game like a very deadly trap that the characters have no chance of detecting, and then, BOOM, somebody is dead.
Simple traps, however, can be used in a lot more places and can be better hidden, especially if they don't really cause all that much damage on their own. They can also be used to set up PC behavior. Take the following simple trap:
The floor looks worn and is covered in bits of debris in places.
Type: mechanical; Perception DC 17; Disable Device 16
Trigger touch; Reset None
A small section of the floor collapses when a character steps in it, exposing a 1 foot pit. Weak Floor(DC 17 Reflex Save or take 1d3 damage and be knocked prone)
This trap is perfect to place in an adventuring area such as an old house or warehouse. Put in one or two while the PC's explore the area. It won't really hurt them, but it will slow them down a bit, and they will search the floor as they move through the house. When the PC's reach a boss or tough encounter, you can place it in an open space. You will artificially limit their mobility because whether or not the floor is weak here, the PC's will expect it, and will likely change tactics a bit and plan on having to deal with a weak floor. If the opponent flies or is somehow immune to the floor effect, (such as being non-corporeal) so much the better. They may also just dive right in; in that case, make sure a few spots in the room are weak. Either way, you've introduced a new element to spice up what may otherwise be an ordinary encounter.