The final part of the ceremony
The Age of Ascension is a rite of passage in several cultures. It generally signifies one's entrance into adulthood.
The Klingon Age of Ascension is the time when a Klingon child officially becomes a warrior.
The first Rite of Ascension has to be taken by the age of 13 in order for a Klingon youth to declare his intentions to become a warrior. (TNG: "Firstborn")
The final initiation ceremony involves the use of painstiks, as the celebrant walks along a line of warriors, intoning: "Today I am a warrior. I must show you my heart. I travel the River of Blood."
The anniversary of the event is a day of ritual and celebration. On the tenth anniversary of Worf's Rite of Ascension (he apparently did it when he was 15) his crewmates aboard the USS Enterprise-D recreated the ceremony on the holodeck. (TNG: "The Icarus Factor")
The Ferengi Age of Ascension is the time when a male Ferengi is expected to leave his family and make profit on his own. In 2351, Quark left home immediately following his age of ascension. (DS9: "Family Business")