In my astronomy class last year, I think I learned more about biology than I did about astronomy. For example, did you know that an octopus has hemocyanin? I also learned about hydroponics. So anyways, what unrelated facts did you learn in class that just seemed completely different from the original content?

Can i take your class?

Uh, I learned what the structures of cocaine, LSD, heroin and crystal meth were in my organic chemistry class, he even showed us how to make speed. Now if I ever take higher level organic chemistry, they'll ask me "Do you know the mechanisms of this reaction?" and I'll answer "No, but I do know how to make heroin from morphine though."

What? That's highly related to O-Chem.

I took Spanish III my first semester of college. My professor was insanely proficient at the language but he had the worst ADD. I learned several historical things about baseball and football in that class.

Related yes, but I don't think this information would be highly relevant in any sort of higher level organic chemistry. The fact that he stressed memorization of multiple random organic compounds and basically ignored the mechanisms of any of the reactions we learned wouldn't really help me later. But I really don't mind, it was my last organic chemistry class.

What is the problem? I don't see a problem as long its factual information and it seems to me your learning science.

We've learnt in chemistry that if you extract the morphium from opium which you extract out of poppy flowers, then you need to add vinegar to make it become heroin.

I learned in Chemistry class that my science teacher played WoW, and was part of some guild or something called "Gnomes gone wild"... or something.
To be a bit more on-topic.
(Note that this was a couple years ago, and I have never come anywhere near WoW, so it's a subject where I'll have a lot of "Hell'f I know"s.)

My senior year in high school was where I learned some interesting facts. In my economics class, all someone, usually me or my buddy, would have to mention is anything about a grocery store and that would derail any lesson/quiz/test/you name it. My buddy worked at shoprite and I worked at price chopper, so me mentioning grocery stores would turn my teacher into a machine. She's in love with wegmans grocery stores. She usually rants about their superior service or their extraordinarily low prices.

One time, we actually talked her into showing us a documentary she had about wegmans. It was sort of related to economics. Wegmans whole sales pitch is, to take the price of an item during a sale and the price of the same item when it's not on sale, and sell it year round for the price in the middle those two ranges so that if you're away or something, you won't miss the sale. Makes sense.

Semi related to OP's post.

In my Health class i have the wrestling coach/Football coach as a teacher. He said that Babies born with HIV/AIDS can be fully cured because the doctor throws medicine over the newborn is it's born. He also said smoking pot gives you a 300x chance of getting lung Cancer.

OH wait I remember something. My English teacher is a twilight fan and had posters of Twilight all over her room. She had news articles and everything. She was like 40 something and fat. It was gross. She would teach us about vampires and the twilight series. :X

In French this year, I learn about as much from my friend (yes, he's Asian) than the teacher. So far he's taught me how to prove that the square root of 2 is irrational, showed me his advanced math tests that he does out of school among other things. Also, we debate random stuff like whether the cookie monster promotes obesity or is just misunderstood or is portrayed in that way because of capitalist propagandaists.

The teacher thinks we barely talk.

My music theory class last year was pretty fun.
Every once in a while we'd have a movie day, where we just sat around for >an hour and a half and talked about what movies had come out lately, what was good, what was bad... etc.
We almost even brought in a boot-legged copy of Twilight to watch (this was before it came out on DvD), but we actually did stuff the day we were gonna watch it.

I saw 8 mile for music appreciation class. Un-censored.

Law Class:
Shawshank Redemption
Double Jeopardy
12 Angry Men
Run Away Jury
Prison Break

Physics Class:
Guitar Hero
Stargate Movie

English Class:
The Matrix 1 & 2

Wait wut... you played the actual guitar hero or...

Yeah, we played guitar hero and I think some wii games.

Nice. We've always tried to get our teachers to let us hook a game system up to the projectors. No luck so far though.

I did the matrix in English too!!

I talk about programming, higher maths, and colleges in math.

In IB Bio we often talk about philosophy.

In English we talk about current events, and psychology.

In history we usually talk about recent movies and analyze them. I'd say this class gets off topic the most, and has the most interesting off topic discussions.

In drafting I talk on SEN everyday.

In IB physics.. We actually talk about physics.

In TOK (last year) I would usually take on the entire class and play devil's advocate for whatever the debate was, and I would usually win

Circuits: play with lego mindstorms
Beekeeping: watch shitty bee movies and learn how to make mead/history of bees. Not entirely unrelated to the subject.
English: listen to stories about the teacher's crazy experiences, like the time a kid died in the school, when a girl went into labor in a bathroom and couldn't get her pants off, how to correctly beat your children, when her son got run over by a truck, the drive by shooting on a bicycle, all while getting a massage.
Transport Phenomena: I learned an awful lot about fluid mechanics. Much more than my fluids class.
Land resources: How to fly an airplane through clouds, how arkansas gets flooded so often (they had 29 inches of rain in one storm), probably some other stories I now forget.
Introduction to Film: we watched a movie every class and talked about it, but that's not really unrelated to the subject. First night was Pan's Labyrinth.