This is old, but someone else might care.
My school has four nights of rush. Three nights informal (usually themed), one night professional. On the informal nights, you come out and meet the brothers. There's food. You chat with each other. They see if you have potential, you see if AKPsi is right for you. We've had 'speed dating' to meet as many brothers as you can as well as game nights. Last night is professional rush. We usually have a speaker and you dress in business formal. This is when your application is due. Each rush is usually three hours long. We expect you to come to at least three nights (other commitments like work or school are acknowledged).
I think we really look for if you are going to commit and bring some professional skills to the chapter. Not a bad reputation of a pledge getting drunk every weekend. Thats just us though.
One thing we specifically look for is- NOT REFERRING TO AKPSI AS A FRAT. Okay. *done with little rant*