What you make it

Introduction
My advice to high school students considering Penn State? Be aware of how vast Penn State is, in every regard. Your entry-level courses, which you will be in for your first four semesters, will routinely have 200 to 800 other students in them. This makes asking questions in class difficult, and finding one-on-one time with your professor impossible. All you can do at this point is pray that your TA speaks coherent English. You will be arriving on campus with thousands of other students, so get used to lines. You will encounter long lines at the gym, at the dining commons, at stores, and at social events. As a freshman, you will get last pick (out of 30,000) for classes, extracurricular spaces, on-campus housing, and parking spots. Be prepared to accept your 3rd or 4th choice for everything (including classes), since the most desirable aspects of Penn State are flooded with applicants. I know countless people who have had to stay at Penn State an extra semester simply because the one class they need to graduate is full. One might think that exceptions are made, but this leads to another warning about Penn State: get used to the word "policy".

Policy is what gives the whirlwind of Penn State a semblance of order, and it is what will deny you access to many of the opportunities you no doubt are looking to enjoy. After all, you beat out 10,000 other applicants to attend Penn State, and there are 10,000 other freshmen to take your place in line. As an undergraduate at Penn State, you very often feel as though you are merely a nameless student, sadly. The only solution to this is to quietly take a number and wait your turn- you will be doing this quite often.

Campus Life and Social Life
Your first month on campus at Penn State University- Main Campus will likely define your entire undergraduate experience. Therefore, it is crucial that you establish friendships early with the other incoming freshmen, as upperclassmen have a nasty habit of socializing exclusively within their cliques. This social path almost always leads you into the hazy greek life. On the other hand, it is entirely possible to make friends through classes or extracurriculars (assuming you get involved). These academic friendships are then inevitably galvanized through drunken chance encounters, beer pong tournaments, or any other alcohol-based activity. This tendency can be a strength or weakness of Penn State, depending on your viewpoint. Those who are socially adept will find ways to navigate through the sea of faces and find a network of friends to spend their time with. Those who are less social will likely be overwhelmed by the sheer number of strangers. Penn State can provide a great social life for both personalities, but be aware that the greek scene, so heavily stressed in the promotional videos, is simply unavailable to non-members. This goes back to your first month on campus- if you want to you must go greek early, else you will be frequenting apartment parties. Advertisement
Academics
There's more than one way to skin a cat, and at Penn State, there are several ways to get an A. This can mean not going to class at all, and teaching yourself (an absolutely essential skill). It can mean befriending a TA to gain a lenient grader (sometimes necessary). It can mean doing the daily crossword in a mandatory-attendance lecture given by a boring, self-absorbed professor, and getting an A for doing little beyond going to class. The point is, they all require effort in some form. Slacking at Penn State very quickly puts you in the average academic category, and with 30,000 undergraduates, you'll graduate with an average GPA held by 20,000 other Penn State grads.
This means that you must find the motivation to push yourself academically, and to willingly take on a greater workload than you might otherwise undertake. Given the alternative (drunken frat parties), this can be a challenge to incoming freshmen. Make an honest assessment of your ability to manage your time when choosing a major, as the more difficult majors require significant chunks of your drinking time.

Student Body
Stock up on hooded sweatshirts- it's the standard issue uniform for Penn State students. They are worn as jackets even when it is 10 degrees out, and as raincoats, as it rains for half the year in State College. There are two outfits for Penn State students: that which you slept in (to wear to class), and that which you hope will get you slept with. Simply change outfits at 8am and at 8pm.
This highlights a duality that is common among Penn Staters. They have a class mode, and a drinking mode. There is little overlap, and they are radically different. It is not uncommon to find the mousy "smart kid" from class drunkenly gorging on pizza at 3am on Beaver Street. When asked where students are from, you will get one of three responses at Penn State: (1) near Philadelphia (never IN philly), (2) Pittsburgh, or (3) a small town in middle of nowhere Pennsylvania. There is no in-between.

In Closing...
When choosing a major, ask what others are majoring in, and pick something else. Your mission while at Penn State is to find ways to associate with the common students, yet academically set yourself apart. Each are vital to your professional success. Good luck!