Orientation is pretty low key. Okay - here's the evidence that I'm likely the biggest pack rat attending USD: I actually still have the orientation schedule from when I was an incoming 1L. You arrive at a certain time and they give you a package of information, which includes a checklist of things you need to do that day. For example, register (they just give you your schedule -- you don't get to select your classes or professors), buy your books, get your student ID card, parking permit and e-mail account, get your assignments, etc. You also have to attend a financial aid presentation - basically they tell you this is a lot of debt and better plan for it (like you didn't already know that, right?). They also have presentations from current students and alumni-- what to expect in law school, e.g., the socratic method, finals, etc. I also remember at some point there being pizza and beer. I think last year, they even organized to go to a baseball game or something (don't quote me on that).
It's just a good chance to get familiar with the campus and meet fellow 1Ls. At all costs, avoid doing any posturing and don't listen to anyone engaging in posturing.