Happy Mahashivaratri! This year its night from 13 to 14 feb (2018)
In the Indian tradition, Lord Siva is revered as Adiyogi (the original yogi), the first and eternal guru and patron of yoga - the art of achieving self-realization, the opening of the Divine in itself.
On the Mahashivaratri Shiva devotees traditionally chant (and listen, as others chant) the hymn of Shri Rudram (aka Shatarudria, aka Rudradhyaya).
A good record of this hymn is available here: https://www.youtube.com/watch?v=gwPuuKPKI6w
You can listen and meditate on Shiva with this hymn. Or listen and conduct Shiva-puja, if you know how.
P.S. There is such an advanced option - to read / listen to this text 11 times in a row.
And for those who asked, Shiva Kavacha (mantra of Shiva for protection from problems and dangers) - https://www.youtube.com/watch?v=SGDxCBKUmZ4