Today is Shivaratri, or the Great Night of Lord Shiva*.
It is Lord Shiva's favorite day, and each time you chant his mantra today it is like doing it 1,000 times.
It is also a day of fasting, and staying up all night chanting His name (which is why the shala in Mysore is always closed on this day).
From Lily at the Dharma Yoga Center:
Celebrated on the 14th night of the new moon in months of February and March, Maha Shivaratri or 'Shiva's Great Night' is known as the wedding day of Lord Shiva and his wife, Parvati.
On Maha Shivaratri day, devotees of Lord Shiva fast for the entire day and recite "Om Namah Shivaya" japa throughout the day. The entire day is spent in intense worship to the Lord. Maha Shivaratri is a blessed opportunity for the aspirant of Yoga, as he who remains vigilant and sincere in his worship on Maha Shivaratri will conquer Rajas [passionate activity]. Furthermore, those who observe vigil throughout the night of Shivaratri are said to conquer Tamas [inertia] entirely!
Let "Om Namah Shivaya" be your mental and verbal mantra all day and night, surrendering yourself completely the Lord Shiva, the representation of that almighty light dwelling deep within you. **
Here in Chicago there is an all-night event at the Sivananda Vendanta Center, starting at 9:30PM. The fast is broken the following morning.
Om Nama Shivaya!
*Lord Shiva represents the Supreme Self dwelling at the right side of the heart and encompassing all of the other gods. He symbolizes renunciation, and is a favorite of yogis.
**From Swami Sivananda: "The two great natural forces that afflict man are Rajas (the quality of passionate activity) and Tamas (that of inertia). The Shivaratri Vrata aims at the perfect control of these two. The entire day is spent at the Feet of the Lord. Continuous worship of the Lord necessitates the devotee's constant presence in the place of worship. Motion is controlled. Evils like lust, anger, and jealousy, born of Rajas are ignored and subdued. The devotee observes vigil throughout the night and thus conquers Tamas also. Constant vigilance is imposed on the mind. Every three hours a round of worship of the Shiva Lingam is conducted. Shivaratri is a perfect Vrata [religious observance]."