Gayatri

One who chants Gayatri mantra one hundred and eight times in the temple of the Lord in three different times, 

1. morning, 
2. afternoon and 
3. evening 

no longer have to indulge in sinful activities. Lord Vyasadeva becomes pleased with such a person and the practitioner returns to the abode of Vishnu.

Source

Conversation between Lord Krishna and Maharaja Yudhisthira.

http://brickinformation.blogspot.com/search/label/AshadiEkadashi