At Texas (which I think is much like SEC type rush), summer rush parties and events are HUGE, and the top fraternities have their pledge classes set before school starts. There is a "rush" week, but there is no set schedule.
I wrote a fraternity rush thread after my son pledged that outlined how his rush went. It really started when he was a senior in highschool and went into overdrive the summer before school. I tried to tell it like it happened, I only knew what he told me, but you can get an idea of what the "pre-rush" events are about.
http://www.greekchat.com/gcforums/sh...ad.php?t=89363