The Clone Wars
This page is about the ancient Jedi Initiate ritual. You may be looking for the episode by the same name.
The Gathering

Yoda leading a group of padawans in "The Gathering"

The Gathering was a rite of passage in the training of Jedi younglings to become Padawans through the creation of their own Lightsabers. It took place on Ilum where the younglings would claim their lightsaber crystals in the crystal caves. The process was a lesson to teach the young Jedi to overcome their own personal fears or failings.