What is the Frat scene?

<p>I have recently been talking to some friends about frats at Penn. As I know, frats are popular at Penn–the “Greek ivy”. I will be attending Penn next year and I was hoping to find out advice on joining/the best ones to join. Could someone give a rundown/short sentence on each frat as well as info on the infamous underground ones? Also, is being an engineer and trying to join a frat a bad idea?</p>