Lamplighting WEEK is NOT ritual
It also varies from chapter to chapter. We didn't have a house, so we met for about 2 hours each night (we were a colony) and our Chapter Consultant (who might as well have been our pledge mom) lead our activities. They ranged from Scavenger hunting to sisterhood bonding

One time we even had to go back to various off campus houses and bake a DZ related cake and decorate it in under 2 hours...the best cake won something, I don't remember what though (was about 10 years ago!!).