Śrāddha or 
Shraaddha (Sanskrit: 
श्राद्ध) is a Sanskrit word which literally means anything or any act that is performed with all sincerity and faith (Śraddhā). In the Hindu religion, it is the ritual that one performs to pay homage to one's 'ancestors' (Sanskrit: Pitṛs),  especially to one's dead parents. Conceptually, it is a way for people  to express heartfelt gratitude and thanks towards their parents and  ancestors, for having helped them to be what they are and praying for  their peace. It also can be thought of as a "day of remembrance". It is  performed for both the father and mother separately, on the days they  became deceased. It is performed on the death anniversary or  collectively during the Pitru Paksha or 
Shraaddha paksha (Fortnight of ancestors), right before 
Sharad Navaratri in autumn.
In practice, the karta (person who performs the 
Śrāddha) invites Brahmanaas (priests) and his relatives and friends that day, treats Brahmanaas (priests) as his/her parent, performs a homa  (fire ritual), and offers balls of rice to the departed souls ("pinda  pradaana", offered to the Pitṛs, the ancestral spirits). The karta   serves the priest with sumptuous food, treating them with all  hospitality,  and concludes the ceremony by giving "dakshina" (fees) to  the brahmanaas. (There are various other actions done to show respect to  the Brahmanaas, like washing their feet etc. during the course of  shraaddha).  Cows and Crow are also considered ancestors in Hinduism and during  Śrāddha the practice of offering food or pinda to cows and crow is still in  vogue. 
Since this is one of the more important and noble "
Saṃskāras"  (rituals meant to cleanse the mind and soul) that the Hindu sages have  envisaged, it is imperative that the performer of the ritual understands  what he or she is doing. Only then will the true intent of the ritual  be fulfilled and the performer of the ritual feel completely gratified.  Else, the ritual becomes just a mechanical exercise for one's part.
In Hindu 
amanta calendar ( ending with 
amavasya ), second half of the month 
Bhadrapada is called Pitru Paksha: 
Pitripaksha or 
Shraddha paksha and its 
amavasya ( new moon ) is called 
sarvapitri amavasya. This part is considered inauspicious in 
muhurtshashtra (electional astrology). At this time (generally September) crops in  India and Nepal are ready and the produce is offered as a mark of  respect and gratitude (by way of pinda) first to the ancestors be they  parents or forefathers before other festivals like 
Navaratri begin. 
Many people visit Hindu pilgrimage sites to perform, 
Shraadha ceremonies, like Haridwar, Gokarneshwar, Nashik, Gaya etc. Haridwar is also known for its Hindu genealogy registers.