As you can see there is several way to achieve your goal :accidental/pathological or intentional/recreational/religious. Even if the first one is very interesting, I will try to focus on the second one.
An ASC can sometimes be reached intentionally by the use of sensory deprivation, an isolation tank, sleep deprivation, lucid dreaming, or mind-control techniques, hypnosis, meditation, prayer, or disciplines (e.g. Mantra Meditation, Yoga, Sufism, dream yoga, or Surat Shabda Yoga).
It can also be attained through the ingestion of psychoactive drugs such as alcohol and opiates, but more commonly with entheogenic plants such as cannabis, salvia divinorum, psilocybin mushrooms, peyote, DXM, ayahuasca, or datura (though less common).
Another effective way to induce an altered state of consciousness is using a variety of Neurotechnology such as psychoacoustics, binaural beats, light and sound stimulation, cranial electrotherapy stimulation, and such; these methods attempt to induce specific brainwave patterns, and a particular altered state of consciousness
During our journey over this blogs, I will try to make you discover (for the novice) this state of mind, using divers medium such as meditation, reading, music ... relating my experience, and as well waiting for your feedback, comments and report as well
As an introduction I will quote wikipedia and specialy the list of States of consciouness and let you discover a bit more by yourself !
States of consciousness
Hope you will enjoy and open your mind !