Here's a List of the trademark "I've Learned something today" from all episodes of Southpark.
Disclaimer: This has been collected automatically using a script I wrote from www.southparkstuff.com. This is by no means exhaustive.

South Park: Season 1

1x2 - Weight Gain 4000
You see, I've learned something today. You can't win all the time. And if you don't win, you certainly can't hold it against the person who did, because that's the only way you ever really lose.

1x7 - Pink Eye
You know, I've really learned somethingtoday. Halloween isn't about costumes, or candy. It's about being goodto one another, and giving and loving.

1x9 - Starvin' Marvin
You know, I think I've learned something today. It'sreally easy not to think of images on TV as real people. [Kenny's headmoves] But they are. That's why it's easy to ignore those commercials,but, people on TV are just as real as you or I.

1x10 - Mr. Hankey, the Christmas Poo
You know, I learned something today. I learned thatJewish people are okay. And that…Channukah can be cool, too.

1x12 - Mecha-Streisand
But you know, I've learned something today. I'velearned that people who want power, a lot of power, always…end up dead.

South Park: Season 2

2x4 - Ike's Wee Wee
Yeah. You know, I've learned something today. Familyisn't about whose blood you have, it's about who you care about. And that's why I feel like you guys are more than just friends. You're my family. [tugs on Ike and moves away] Except for Cartman.

South Park: Season 3

3x5 - Jakovasaurs Eric, but I've learned something today. You see, animal species comeand go. It's all a part of natural evolution. The jakovasaurs would have gone extinct if we hadn't interfered. Because their particular form of life simply wasn't practical. [with a much better voice box] We can't go around saving every form of life, any more than we can kill them all. We have to let nature run its course. [silence]

3x6 - Sexual Harassment Panda [approaches Petey and the boys] No! Don't you see? Th-the panda's right. Boy, what a great message he has! When you sue people, you just end up causing a lot of problems for society. Uhwell, I've really learned something today. All I could see was the millions of dollars coming to me and I didn't care about where the money came from. Well, I'm no longer doing sexual harassment lawsuits in schools! They're too vague and two easily corruptible. Thank you, Sexual Harassment Panda!

3x8 - Two Guys Naked in a Hot Tub (2)
But you know, I learned somethingtoday. I used to call you guys Melvins. But you're just kids, like me.We separate you in school because you talk different and you study toohard, but we've proven tonight that we can all get along.

3x10 - Chinpokomon No, Kyle. You see, we learned something today. This whole Chinpokomon thing happened because we all followed the group. We only liked Chinpokomon because everyone else did. And look at the damage it caused. You see, Kyle, I learned something, just now. It is good to go with thegroup. A group mentality is healthy, sometimes.

3x13 - Hooked on Monkey Fonics
[onstage, takes the mic from Dio] Calm down, papá! [Papá looks at Mom] Everything is all right. [the kids look at him] You see, I've learned something today. Public schools may be a bit lacking in education, but it's the main place where children learn all of their social skills. You can't teach a child social skills. They have to learn them themselves. And the only place to do that is on the playground, in the cafeteria, and so on. [his parents listen] Don't you see, papá? That's what happened to your daughter. You tried so hard to keep her from anythng sexual, and now look at her. She's a God-damned whore, papá. [Rebecca is listening]

3x14 - The Red Badge of Gayness
Yeah, but you know? I think you've learned somethingtoday. You've learned that you can't rewrite history. [Cartman eyes aphone…] You see, history is forever, […and anempty schnapps case next to it] and everything happens for a reason.[Cartman turns and walks] Sure, you can try and change the past, but usually you kno-

3x17 - Worldwide Recorder Concert
Yeah, but you know? I learned somethingtoday. We were so worried about how cool we looked to those New Yorkerkids that we forgot: we're already totally cool, even if we don't knowwhat queef means. [Kyle and Cartman grin]

South Park: Season 4

South Park: Season 5

5x2 - It Hits the Fan
You see, we've learned something today. Swearing can befun, but doing it all the time causes a lot of problems.We're all saying the S-word too much! [Ike hops in].The knights of Standards and Practices were created to make sure that bad words were kept to a minimum. "Curse words" They're called that because they are a curse. We have to go back to only using curse words in rare, extreme circumstances.And besides, too much use of a dirty word takes away from its... impact. We believe in free speech and all that, but... keeping a few words taboo just adds to the fun of English.[camera cuts to him] So please, everyone, From now on you've got to try and watch your language. [murmurs and a smattering of applause come from the audience]

5x6 - Cartmanland : [leaves the pew to face Stan, teary-eyed] Do you?! Do you, Stan?! Because all my life I was raised to believe in Jehovah! To believe that we should all behave a certain way and good things will come tu us. I make mistakes, but every week I try to better myself. I'm always saying, "You know, I learned something today..." and what does this so-called God give me in return? A hemorrhoid. He doesn't make sense! [to God] What is your logic?! [feels a pang in his ass] Ow. [tends to the pain]

5x12 - Here Comes the Neighbourhood do. But, I guess I learned something today. You see, even though kidsat South Park make fun of me, I still like hanging around them morethan snobby rich kids or, lions. Even though I may be different fromthem, I still like my old friends best.

South Park: Season 6

6x2 - Jared Has Aides but you know, I've learned something today. It would have been wrong toexploit Butters' weight loss. Becuase then lots of fat people wouldhave believed it. And then gone and eaten a ton of Chinese food insteadof dieting properly. They'd still be fat and, we'd be responsible fortheir shattered dreams.

6x15 - The Biggest Douche in the Universe see, I learned something today. At first I thought you were all stupid,listening to this douche's advice, but now I understand that you're allhere because you're scared. You're scared of death and he offers yousome kind of understanding. You all want to believe in it so much, Iknowyou do. You find comfort in the thought that your loved ones arefloating around trying to talk to you, but thnk about it: Is thatreally what you want? To just be floating around after you die, havingto talk to this asshole? [the audience is listening] Weneed to recognize this stuff for what it is: magic tricks. Becausewhatever's really going on in life and in death is much more amazingthan this douche. [more audience listening, reflection. Kyle ispresent. One man claps, then others clap with him, then murmurs areheard]

South Park: Season 7

7x2 - Krazy Kripples
I told you, lock-ins at the rec center always work. And you know, I've learned something, too. I was player-hatin' Christopher Butthole Reeve because he got more attention than me. But just like... y-you guys, I need to learn to control my a... anger.

7x13 - Butt Out
No it isn't, you fat turd! Because, I've learned something today. You just hate- [to Stan] See, I knew it. It wasn't the tobacco companies' fault that we smoked. It was our fault, us! We should all take personal responsibility instead of letting fat fascists like him tell us what to do!

South Park: Season 8

South Park: Season 9

South Park: Season 10