The Danger Room has played an important role in the everyday lives of the X-Men since the beginning. It provides a central and controlled location for training where the X-Men can learn to control and develop their abilities in normal and combat-like situations.
The original Danger Room employed many mechanical weapons and dangers including flying projectiles similar to missiles, obstacle courses, trap-floors, fire, crushing walls, and much more. The layout of the Danger Room has not changed considerably since its earliest mention. The room itself is quite large, and there is a central control room and observatory overlooking it where the entire room can be controlled by a single person.
Since the beginning the Danger Room has underwent a series of upgrades. The first was the addition of robots to the room for combat training. Later, Shi'ar technology was incorporated by Beast, upgrading the room to incorporate realistic holograms to the training and adding to the weapons and traps that the X-Men faced while training.
At some point the Danger Room has gained sentience. It is unclear when this happened, but it was revealed that Professor Xavier was aware it and chose to leave it imprisoned in the room. The room began to attack students that were inside, and its core was accidentally freed by Wolverine. Constructing a body resembling a human female, Danger has become an enemy of the X-Men. Currently the Danger Room is inactive as it has lost its control system. Prodigy, a student at the Xavier Institute, constructed a "Danger Cave" with similar functionality before losing his powers as a result of M-Day.
Age of Apocalypse
Killing zone: This zone resembles the actual Danger Room, it is a state of the art in training technology and it is located in Wundagore Mountain at Magneto´s mutant Sanctuary.
Danger Room appears in every X-Men series but it was most commonly used in X-Men Evolution where it was not only used to train and practice but was also used to clean the X-Jet,use a training simulator to simulate results and one of the more common uses was to protect something of value to the X-Men or to protect someone like Professor X or injured Teammates while away on a mission or during a siege or attack on the X-Mansion, and for a very short time was used to protect Cerebro from Mystique while everyone was away on a mission.
X-Men: The Last Stand
It appears at the begging of the movie. It is used by Iceman, Shadowcat, Rogue, Colossus, Wolverine and Storm, the latter two were leading the training session. The team was fighting a robot clearly as a reference to Sentinels.