Here is a new trap to pull on your players.
Have the players come across a "T" in the hallway or dungeon. A deep spiked filled pit sits open 5 feet from the "T" in the hallway. The pit can be only 5 foot wide and can be easily jumped. The trap is this: just on the other side of the pit is a portable hole that has a illusion on the floor over it. The portable hole is 10 feet deep and is filled with 8 feet of water. Standing around the connor are 2 bad guys. When the first player jumps across he or she will jump into the water filled portable hole. The 2 bad guys will run out and fold up the portable hole and trap the player with-in. The water is in the hole for the sole purpose of a player cant jump out if he or she is swimming. You could then have the bad guys take off with their new hostage, instead fill the hole with acid and have the bad guys fold it up. Or for higher level players, have the bad guys throw the portable hole into a bag of holding and kill the player.
Just a thought I had today.