Author - SL Huang (aka MathPencil)

By https://www.flickr.com/photos/namlhots/5484492086/in/set-72157618477446636 [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

1. Classes are referred to by number, NOT by name (it’s 18.014, not “Calculus with Theory” — we usually didn’t even know the names).
2. Majors are referred to by number, not by name (it’s course 8, not Physics).
3. Buildings are referred to by number, not by name (it’s Building 2, not . . . oh, you get the idea).
4. There’s no central dining hall; you can’t talk about “the MIT dining hall.”
5. There’s no central library; you can’t say, “meet me at the library” unless you already know which one.
6. There’s no meal plan.  You have a student account linked to your student ID, but you pay for what you eat, and the account is just money and can equally be used for things like books.
7. The campus store is called The Coop (pronounced like the thing a chicken lives in, not Co-Op), but some of the more theoretical science and math texts are only at Quantum Books.  The student card can be used both places, as well as at a few local eateries.
8. MIT has its own slang — and a lot of it.  Punt, tool, cruft, hack, psets, fingering, Twinkies, IHTFP . . .
9. As of some years ago, you can’t have more than two majors, so triple majors are out.  You can have up to two minors as well, but not every subject offers a minor (computer science^[1] doesn’t, for example; if it did I would have one!).
10. You can’t say you’re majoring in “engineering.”  First of all, see #2, and second of all, there’s no such major — 10 out of the (approximately) 24 different courses of study are different kinds of engineering.
11. The computer clusters are called “Athena clusters” and mostly run Linux (at least, they did when I was there; they’d started to get a few Windows machines my senior year for certain kinds of software).
12. Some people go by their Athena usernames.  Even the people with unpronounceable usernames, such as sets of initials, get them used as nicknames occasionally.
13. Dorms all have their own character and culture and students choose where they live, so the dorm a student lives in can say a lot about that student’s personality.  The various dorms / sections of campus (East vs. West) / dorms vs. frats all mock and judge each other — sometimes gently, sometimes . . . less gently.
14. It’s not unusual to have your own room as an undergraduate, though you can have a roommate if you want one.  I had my own room from sophomore year on; most students have roommates during
    Drinking and partying happen if you want [them], but […] they’re incredibly easy to avoid if you don’t
    freshman year but I could have had a single that year too if I’d wanted one.  Depending on the dorm, rooms can be quite spacious rather than the stereotypical college closet.
15. Drinking and partying happen if you want that kind of college experience, but unlike at some other universities, they’re incredibly easy to avoid if you don’t want them, and plenty of people have no interest in that kind of student life.
16. Despite the number of fraternities, Greek life is little more than a footnote to those who aren’t in it; the most I can say about frats is that I had a few friends who were in them, and I think I was inside a frat a grand total of one time.
17. Aside from premeds, the undergraduate student body is remarkably uncompetitive, because classes are hard enough that intra-student competition becomes a lot more meaningless.
18. There’s no grade inflation.  Professors do use grading curves at their own discretion, usually to align the mean to a certain number (say, 70) and the standard deviations to the right places.  I’ve never heard of an MIT professor curving scores down; there’s rarely a problem with exams being too easy.
19. Unlike at Caltech, women are not a rarity — the undergraduate ratio is something like 40/60 women.  In certain classes, however, the gender ratio is far more skewed; I was one of only two women in my 18.034 class, and was the only woman in my 18.515 class.  (These are both super theoretical math classes and had probably totaled 13 and 8 people respectively.)
20. MIT is reasonably diverse.  There are a lot of international students, and any fiction set at MIT with no Asian-American characters I will call shenanigans on.  Other minorities have smaller populations, but almost every class or student group or dorm will have at least some African-American and Hispanic students, and one of the rarest demographics is actually the Midwestern white boy.^[2]
21. If you pick a non-math, non-science academic subject (literature, music, philosophy, history . . .) and start talking to an MIT student about it, it’s more likely than not that that student is way more knowledgeable than the average person about it.
22. If you pick a pop culture subject that isn’t science fiction/fantasy, however,
    My friend didn’t realize we had a cheerleading squad until after we had graduated.
    all bets are off.  Some MIT students are up on popular media; others are completely clueless.
23. Students tend to be highly politically aware on a general level, though may or may not keep up with current events while in college.  Students who do follow politics tend to do so passionately, no matter where on the spectrum they fall (and yes, MIT has students with a HUGE diversity of political perspectives, from intensely conservative to burningly liberal and everything in between — or off the axis entirely).
24. Students tend to be either highly religious or highly nonreligious (casual Sunday churchgoers are rare).  Atheism/agnosticism are much, much more common than in the general population, almost to the point of being the default assumption, but people who are religious aren’t uncommon, and are extremely well-thought-out and passionate about their religions.
25. In general, MIT students tend to be passionately intense about every aspect of their lives, from hobbies to personal philosophies to independent projects.  You can find student groups related to almost any interest under the sun, and the people in them are usually really into them.
26. Sports are a lot smaller deal than at other schools, and the ones with hardcore teams tend to be sports such as fencing and pistol, and not, say, football.  I didn’t even know we had a football team until my junior year.  (My friend didn’t realize we had a cheerleading squad until after we had graduated.)  This isn’t meant to be judgmental about football and cheerleading; my point is just that they have next to no impact on student life so it’s easy not to notice we have them, which is the opposite of most schools.
27. University rivalries: Harvard and Caltech.  These rivalries are not about sports.^[3]
28. Cross-registration is allowed between MIT and Harvard and MIT and Wellesley.  Every once in a while I’d run into a Harvard or Wellesley student,
    Geek traits are sexually desirable.
    and I knew a few guys dating Wellesley girls.  I took one course at Harvard and it was easy to do; I also knew a few other people who did it.  I didn’t know anybody who tried MIT-to-Wellesley cross-registration — I’m sure it was equally doable; it just wasn’t common.
29. You expect the math/science/engineering education to be good, but humanities classes are also excellent (usually just as high-caliber).  There is an eight-class humanities requirement, but many students take many more than that by choice.  You can also major in humanities subjects, which a fair number of people do, sometimes as a double major but I did know a few single-major students in literature or history of polisci.^[4]
30. There’s a four-class PE requirement, but you can satisfy it with awesome things like ping-pong and pistol.  You also can’t graduate without taking a swim test.
31. Hygiene is often considered way more optional than it should be.
32. MIT has a 5-point grading scale, so a 5.0 is someone with a perfect GPA. 
33. There are no Latin honors or class rank.  You cannot graduate summa cum laude from MIT — no, not even if you’re Tony Stark.
34. Mass transit in Boston is so good that almost no one has a car.  I think I knew one person who had one.
35. The subway is called the T.  The T line that goes to MIT is the Red Line, and the stop is Kendall Square.
36. In some ways dating is easier at MIT because geek traits are sexually desirable.  In other ways it’s a mess because everybody gets so in their heads about it.  Some of my friends didn’t date until they got to MIT because of not-fitting-in issues in high school; but a lot of us — sometimes overlapping with the first set — find dating post-MIT a lot easier, because the social stakes and hangups regarding it are a lot lower in the real world.^[5]

Disclaimer: All of this is true when I was there; some of the factual specifics may have changed.