Indeed Lord shiva is associated with destruction, when there is destruction there is also chaos in the world. He also destroys ignorance the state of not knowing, in bringing us knowledge, wisdom, etc.
Mahashivaratri, is the great night of the the Lord. celebrated by many, it is always on the waning phase of the moon, trayodashi or chaturdashi. thirteenth or fourteenth day leading up to the new-moon. It is a very auspicious night in where staunch devotees stay awake the whole night and worship.