In June or July of each year, students commemorate their spiritual teachers (Gurus) with a big festival in India, but also in many parts of Asia. This festival is always celebrated at a full moon (Purnima) and takes place this year on 3rd July 2012 [*].
In Hinduism, this day is also dedicated to the wise Vyasa who is connected to vital Indian writings, like the Vedas, a significant collection of religious scripts.
The legend says that Vyasa was born on Guru Purnima and began later with the writing of the Brahma Sutra on this full moon day. The festival is therefore also called Vyasa Purnima. Often, these texts are read and symbolic gifts are presented during the celebration.
In Buddhism, Buddha is commemorated, who held his first sermon on this day in Sarnath, Uttar Pradesh.
It is a valuable idea to show gratitude towards your teacher and to cherish their memory. The Western world can surely learn one thing or two from the Eastern world.
[*] If looked at precisely and astronomically, the full moon in India takes place on 4th July, shortly after midnight at 12:21:54 am (IST). But because all festivities are stretched over the course of days, this is not really noticeable.