Ours is different every year. I can't remember what the song was for Relay 13 but I know it REALLY got me.
Same with Luminaria ceremony.
Luminaria Ceremony is the reason I Relay. My freshman year, the first time I became close with some of my new sisters (we do recruitment in the spring) was when they all came to give me their hands and shoulders and hugs when I bawled like a baby during the silent lap. While I had loved DG already, those people I truly didn't know that well giving me as much love and support as I had gotten from my best friends back home really sealed the deal for me.