Season Five, "Raiders of the Lost Art"
He's alive! In one of their most shocking (and insane) twists ever, Chuck's father Bart is revealed to be alive and says he faked his own death to protect his son and Lily.
Season Five, "The Princess Dowry"
Serena's got a secret sister—her cousin Charlie. Yes, William van Der Woodsen slept with both Rhodes ladies. Add that to giving Lily fake cancer, and he's pretty much a winner!
Season Five, "G.G."
Going into Blair's wedding to Prince Louis, the only thing fans were wondering was how she was going to bail on it. Turns out, we were all fooled as she actually said "I do," which prompted the Prince to turn into a royal monster. Blair soon flees. Ah, ain't love grand?
Season Five, "Riding in Town Cars With Boys"
Chuck and Blair, who had just decided to break up with the Prince, hit a roadblock (literally) and fight for their lives. Unfortunately, Blair loses her baby in the car accident. Chuck barely makes it through, and Blair believes it's because she made a pact with God. Yes, you read that right.
Season Five, "Yes, Then Zero"
After a summer of nonstop speculation, the season-five premiere reveals that Blair is with royal child. Oh, and Dorota is pregnant, too.
Season Four, "The Wrong Goodbye"
Sweet Charlie Rhodes (Kaylee Defer), Serena's cousin from Florida? Yeah, not really Charlie! Turns out Charlie's mother decided to hire an actress named Ivy to pretend to be her daughter. Crazy? Yes. Entertaining? Yes. Realistic? Not so much, but who cares? The reveal was awesome!
Season Four, "Empire of the Son"
After several episodes of being undercover friends, Blair and Dan decide to test the depth of their feelings with a kiss. Naturally, the episode ended on a freeze-frame and fans were left to debate on the non-couple's status for five brutal weeks. Hurts so good.
Season Four, "Gaslit"
Serena relapses! OK, not really, but she and everyone else thought she did when Juliet (with a little help from Jenny and Vanessa) set her up. Hey, their plan was so convincing that Serena checks herself into rehab, believing she actually overdosed.
Season Four, "Double Identity"
Seaon four began with one question: Is Chuck Bass alive? Turns out, he was dead. Well, metaphorically. After being rescued by a French cutie, Chuck decided to change his name and live as a mere commoner. That is until he ran into Blair in Paris.
Season Three, "Last Tango, Then Paris"
Georgina returns! With a baby! That she says is Dan's! Of course, instead of asking for a paternity test (who needs that?!), Dan takes Georgina and Milo in and becomes father of the year. Except he's not actually Milo's father.
Season Three, "Last Tango, Then Paris"
After Blair fails to show up at the top of the Empire State Building, a depressed Chuck devirginizes Jenny. He then decides to hide the truth from Blair by trying to propose to her. It doesn't end well: Jenny is banished from the UES and Chuck gets in Paris after being rebuffed by a devastated Blair.
Season Three, "Inglorious Bassterds"
Desperate to save his hotel and father's legacy, Chuck does the unthinkable: "sells" Blair to his uncle for one night. Yeah, it's arguably this controversial show's most controversial storyline ever.
Season Three, "The Hurt Locket"
While we were told, via Chuck, that his mother died while giving birth to him, it turns out Bart lied to him. Chuck's mother returns and kicks off a major downward spiral for her son, natch.
Season Three, "The Treasure of Serena Madre"
The lesson we learned from Serena's short and ill-fated affair with Nate's handsome cousin Tripp (Aaron Tveit)? Don't sleep with a married politician, because you will get into a car accident with him, where he will leave you unconscious at the scene of the crime, but not before making it look like you were driving. Oopsies!
Season Three, "They Shoot Humphreys, Don't They?"
Hilary Duff guest stars as a famous actress Olivia. Olivia dates Dan. They decide it's a good idea to have a threesome with his BFF Vanessa. Hey, it's one way to shed your good-girl image.
Season Three, "Rufus Getting Married"
Remember that time Rufus and Lily's secret love child Scott came to the Upper East Side to find them? No? Don't worry, we're pretty sure they don't remember it either.
Season Two, "The Wrath of Con"
Lily has Serena arrested. Ouch.
Season Two, "The Age of Dissonance"
Dan sleeps with his teacher Ms. Carr in a closet. Nothing to add here.
Season Two, "It's a Wonderful Lie"
Gossip Girl's first major death? Chuck's father, Bart, who died in a car accident after learning that his wife was leaving him for a washed-up '80s rocker. Way to rub salt in the wound, universe!
Season Two, "In the Realm of Basses"
Blair makes an uh-oh! While viewers were expecting the introduction of Chuck's uncle Jack (Desmond Harrington) to be pretty juicy, they were left shocked when it was revealed Blair had slept with the elder Bass on New Year's Eve.
Season Two, "New Haven Can't Wait"
While Blair and Serena have had their share of fights over the years, our favorite has to be their catfight (which included headband pulling!) when the BFFs visited Yale.
Season One, "Woman on the Verge"
Frustrated by Serena's erratic behavior, Dan turns to his good friend Sarah...who is actually the evil and conniving Georgina. And by turns to her, we mean he hooks up with her. Sadly, it won't be the last time Dan hooks up with Georgina. (Let's pretend the whole gang's college stint was just a dream, OK?)
Season One, "All About My Brother"
Set in motion by Georgina's return to the Upper East Side, Serena unleashes one doozy of a confession on Blair in the episodes' final moments. "I killed someone." Boom.
Season One, "All About My Brother"
Back in 2007, Gossip Girl's big gay reveal was a big freakin' deal. So who was it? Serena's little brother Eric, who was secretly dating Asher, Jenny's closeted fake boyfriend.