Laylatul Qadr - The Night of Power is a great and powerful night that is better than a 1000 months (83 years and 4 months).
For the virtues of the night of power and in particular the last ten days of Ramadan, see here. To know how to seek the great night and suggested practices for this night, check here.
Aaisha (RA) reports: "I said: 'O Rasulullah (Sallallahu Alaihi Wasallam) should I find myself the "Laylatul Qadr", what shall I pray ? Rasulullah (Sallallahu Alaihi Wasallam) replied: say, “Allaahumma innaka afuwwun tuhibbul afwa fa'fu anni” "O Allah, You are most forgiving, You love forgiveness, so forigve me." (Tirmizi).