In "Fry and the Slurm Factory" (which first aired on November 14th, 1999), Fry becomes enamored with Slurm, a neon-green beverage touted for its "highly addictive" qualities. When the gang wins a free trip to the Slurm Factory, Fry, Bender and Leela do some digging to discover that the drink is actually the anal excretion of a giant worm dubbed the "Slurm Queen." And yet, despite his disgust, a thirsty Fry keeps on drinking Slurm.

"I certainly drink my share of caffeine every day," says Cohen, "and there were all these other variants of caffeinated, alcoholic beverages. Slurm is our version of all that kind of heavily-marketed, addictive stuff. That episode is kind of memorable to me generally because we were starting to loosen up about our material a little bit. We had been trying maybe a little too hard before that point to tell [viewers] that the crew is all family that sticks together and blah, blah, blah, and that episode I think is a little more fun."

In "Xmas Story" (December 19th, 1999), John Goodman guest stars as a killer Santa Claus robot that's been misprogrammed to invariably find everyone to be naughty. Armed with a "sack of horrors," the bot ventures out after sundown each Christmas Eve (now simply referred to as Xmas Eve) to annihilate everything in its path. When Fry and Leela encounter Santa on the streets of New New York, he bellows a hearty "Ho, ho, ho!" before his eyes weaponize into an evil grimace.

"Robot Santa actually dates to very early discussions that I had with Matt Groening about the development of the series from well before it was on the air," Cohen says. "The eyes rotating – that was, I believe, something [created] entirely by the animators. That's one of those things where, you know, we're just watching the rough animation when it comes in and we see that and go, 'Hey! I wish we had written that. That seems pretty clever, and I'm going to get credit for that later.' I believe that was the director's choice, or maybe the storyboard artist – somebody in the pipeline at Rough Draft Studios threw that in."

In "Put Your Head on My Shoulders" (February 13th, 2000), Bender starts a computer dating service to make a quick buck ahead of Valentine's Day. But before that, he briefly enters into the pimping business, which gets him into some legal trouble but also finds him devising a meme-worthy swagger that helps solidify his reputation as Futurama's most colorful robo-rapscallion. 

"If the crime Bender commits is being the pimp, it's because he likes wearing a fur coat and walking around with sexy sunglasses," Cohen says, insisting that Bender's unscrupulous activities don't make him an evil robot (like, say, Robot Devil). "It's not because he wants to be a human trafficker who – when I say human, I mean fembot – wants to traffic in fembot lives and make their lives miserable. He's just having a one-man party. So it's fine, it's fine!"

In "War is the H-Word" (November 26th, 2000), Leela flouts the Earth Army's no-women policy and joins the war effort against Spheron I (a planet populated by hilarious bouncing-ball aliens), disguised as a man. Taking the name "Lee Lemon," she soon attracts the attention of General Zapp Brannigan, who's long nursed a crush on Leela and quickly develops romantic feelings for this strapping male recruit, giving Lee a solid handshake and commending his hand for being "soft as a velvet child."

While writing the script, Cohen says the episode's writers raised the question of Brannigan's sexual orientation. "We're having a discussion, 'Wait, are we making a more general comment about Zapp Brannigan's sexuality? Is he straight? Is he gay? What are we trying to say here?' Ultimately, we actually came to a decision on that topic, which is, 'No, he's Leela-centric.' In any form, he's attracted to Leela. That's Zapp Brannigan's sexuality in a nutshell. You can do anything to Leela, and he'll still be attracted to her."

In the Emmy-winning "Roswell That Ends Well" (December 9th, 2001), Cohen and Groening break the rule they set down while devising the show – no time travel! – to send the Planet Express crew to Roswell, New Mexico, circa 1947. In an episode crammed with indelible scenes and allusions to sci-fi films like Back to the Future and The Terminator, Fry creates the ultimate time-travel paradox as he accidentally gets his grandfather nuked and then sleeps with his grandmother, thereby becoming his own grandpa.

"We're all in hysterics in the writer's room about it – but then having that sobering moment of, 'I don't know if we can do that on TV,'" Cohen recalls. "The scene of the character sleeping with his grandmother – you haven't seen that a lot on television. It's a little disturbing. So we had to address it very carefully and make sure, obviously, Fry didn't realize it was his grandmother."

In "Godfellas" (March 17, 2002), Bender gets launched into deep space after taking a nap in a torpedo chamber. While drifting through the universe, he becomes an incubator for a civilization of tiny, human-like "Shrimpkins." After his attempts to play God go horribly wrong, he encounters a luminous God entity that offers sound advice for aspiring deities: "You have to use a light touch – like a safe-cracker or a pickpocket." Or, as Bender suggests, a guy who burns down a bar for the insurance money.

"Just as we had expert physicists and computer scientists and mathematicians on the Futurama writing staff, we actually did have an actual theologian – I don't know if that's the correct term – a person with a degree in comparative religion," Cohen says, naming former Futurama writer Eric Kaplan, who now works on The Big Bang Theory. "The episode itself was written by Ken Keeler, who has been one of our most prolific and thoughtful writers over the years. So somewhere between Ken and Eric Kaplan probably was some of that philosophy creeping in there."

In "Jurassic Bark" (November 17th, 2002), Fry gets his hands on the fossilized remains of his beloved dog, Seymour. Fry hadn't seen his dog since he'd gotten frozen in the cryogenics lab 1,000 years earlier, and Professor Farnsworth figures out a way to clone the dog and bring him back. But Fry ultimately decides against it, assuming that Seymour moved on and lived a happy life after Fry disappeared. Then comes one of the most tear-jerking montages ever put to animation, when it's revealed that Seymour spent the rest of his years waiting patiently outside Panucci's Pizza for his master to return. 

"Notice that I'm sadistically chuckling at this thought of the dog dying . . . I apologize. I shouldn't be laughing. I'm sorry about that," Cohen says. "It's not a laugh of humor, but a laugh of triumph. Whenever we're hoping to get fans to tear up and it works, I have this little momentary, sadistic laugh of triumph."

For the DVD film Bender’s Big Score (November 27th, 2007), the extras include a 22-minute episode of Everybody Loves Hypnotoad, a hit TV show from the future that stars the Hypnotoad, a minor Futurama character that appears throughout the series. Sitting completely motionless, the Hypnotoad emits a deep droning sound and makes colorful googly eyes, hypnotizing everyone in sight.

"What happens is you think only a second or two has passed. Meanwhile, you have missed an entire day of school, college, work, whatever," Cohen explains. "Hypnotoad is a shining, glowing example of a character who we wrote as a one-time joke, not expecting it to ever come back again. And we decided we liked it too much and we kept bringing it back over and over and over again . . . It became this weird stand-in for just the mindlessness of everything and anything, particularly TV."

In "Attack of the Killer App" (July 1st, 2010), the crew rush out to buy the new "eyePhone," a device that bears a striking resemblance to the iPhone and, even more presciently (since it would be another three years before it would be released), Google Glass. When Fry goes to the Mom Store to buy the item, he's warned by the teller that it costs a ton of money and has poor reception and low battery power, to which Fry replies as any hardcore Apple buyer would today: "Shut up and take my money!"

"It's one of the first episodes we did when we came back on the air on Comedy Central after a long hiatus of cancelation, and one thing that happened while we were off the air is that technology in our daily lives did evolve tremendously," Cohen says. "This particular line . . . at the time we put it in the script, I said, 'This line is going to be quoted and remembered.' It's rare that I feel like we have captured something so clearly and distinctly, and that was one of those moments. I felt like that was a rare opportunity for a show set in the year 3000 to nail something happening in the current day."

In "Reincarnation (September 8th, 2011), the animators showcase their abiding love for animation, creating a three-part episode that reinvents the show in three different ways: as a Twenties-style black-and-white cartoon, an Eighties pixilated video game and a piece of Japanese anime. The episode is full of sweet, touching moments – like when a classic-looking, black-and-white Fry almost proposes to Leela, right before they get frozen in crystal dust – but also tricky writing challenges and obscure animation references that would appeal to the show's nerdiest fans.

"You hand this script to the animators, and they have a heart attack on the spot. I mean, they may literally have dropped dead on the spot. Not only do you have to redesign every single thing on the entire show – all the characters, all the backgrounds, everything – but you have to do it three times," Cohen says. "Luckily, they were willing to kill themselves to do this."