What is pref night?

[Kirain]

I'm a tad confused at the moment. So apparently there are underground fraternities at my school in addition to the recognized IFC fraternities. However, all the fraternities, both recognized and underground were tabling together on campus so I didn't know there was a difference except now I know the underground ones rushed last week and recognized ones are rushing this week.

My initial thought was the rush as many fraternities as I can and see which ones give me a bid. So having been through rush week last week with a underground fraternity, I received a bid.

However, this following week is the official rush week for IFC recognized fraternities on my campus and they all seem to have events scheduled at the same times, so how do I go to all of them? Am I suppose to make up my mind and just rush one? All of them also have something called a "Pref Night" at the end going from 6-10PM.

I was hoping to rush at least two of the IFC fraternities. But since all their events happen at the same time, would it be rude of me to leave one and go to another one late? Would I be able to attend multiple fraternities' pref night as well?

Sorry I'm just a bit confused, hopefully you don't find this silly.