Yup, SKchickie's right.
The New Member Induction Ceremony is a ceremony in the University Auditorium for all the girls. At that point you don't know which house you've been invited to, but just the fact that you're present means that you've been invited somewhere (b/c girls who do not receive bids get phone calls that morning). That's also the time when the Pi Chis reveal their affiliations.
The first round is super long, but in reality there aren't 19 parties. You'll go to 15 parties and have four lounges. During the lounges you just sit around in a lecture hall in Norman and hang out. So it'll be a nice break.
ps: the video round is awesome. All the videos brought me to tears...and they weren't even MY sisters!