The devotees of Shiva perform various religious activities such as Rudraabhishekam (an activity where the devotees pour 108 urns of water and other liquids on the lingam) while reciting the phrases from the holy texts and worshipping with Bilva Patra (a type of leaf).
Another aspect of Mahashivratri is that devotees after fasting for the whole day, keeps themselves awake for the whole night on this auspicious day. This is one of the most important rituals that is followed by all age groups and gender of devotees. To remain awake at night, devotees engage themselves with various religious activities at Shiva Temples or at home such as listening to spiritual, religious discourses, tales, stories, mythologies about Lord Shiva.
The devotees of Lord Shiva believe that by fasting the whole day and remaining awake the whole night amidst chanting of the hymns of Lord Shiva will freed them from the cycle of birth and death and they will attain salvation to become one with the soul of God.
Most of the devotees and pilgrims visit the nearest Shiva temple along with family members, relatives and friends on this special auspicious occasion. They spend the entire night being awake and witnessing the pujas and rituals conducted in the temple premises with great devotion and dedication. It also gives a spiritual good feel for all the devotees and pilgrims to a great extent. On the other hand, common people indulge in watching movies that are devotional and related to Hinduism in theatres and television on this particular night in order to be awake.
Yes, there are many levels of worship and wonderful enough Shiva manifests himself at all of these levels equally. Just the lower level of awreness the harder it can be to recognize him. In the higher traditions meditations and/or pujas are performed all night long. In the highest traditions a continuous meditation and identification with Shiva at all levels of the being is performed for a perfect and total identification (Samyama) of the worshipper with Shiva.