On Thursday, Parks and Recreation will air its 100th episode, after six seasons of brilliant comedy crack that kept us coming back for more. These years have been full of some truly special moments, like celebrity mini-horse Li'l Sebastian, the moonshine drink-off showdown with Ron's mom and one-liners like "Treat Yo' Self." But where did those moments come from? We got on the phone with Greg Levine, a Parks and Rec script coordinator, fact-checker and occasional writer – who has attended every single table read of the show – to find out. Above: Li'l Sebastian, and the Real Horse That Inspired Him Nothing got the Pawnee crew – or the show's fans – more excited than the arrival of Li'l Sebastian. The tiny horse made April (Aubrey Plaza) smile, Leslie (Amy Poehler) squee, and even Ron (Nick Offerman) giggle like a girl and clap his hands with joy. Li'l Sebastian went on to become a fan favorite and de facto mascot for Parks and Recreation, even after he died in his eponymous episode. Nobody can remember who pitched the name Li'l Sebastian, Levine said, but they definitely remembered what inspired him: Einstein. No, not the theoretical physicist – the real-life "Smallest Stallion." Long before Li'l Sebastian was a character the writers on the show had a habit of looking at pictures, videos, and stories of the little horse for LOLs. "The writers' room was obsessed with Einstein," Levine said. "When the Harvest Festival story was taking shape and we were going to do the actual 'Harvest Festival' episode there was talk about how all these small towns have local heroes, or like a very famous site. So it was decided, 'Why don't we have a tiny horse be the centerpiece of Harvest Festival?'" Now Li'l Sebastian is a centerpiece of the show, even if it took Ben a long time to figure out what the big deal was. //www.youtube.com/embed/mXlkfZsgPmo

'Treat Yo Self!' Over the years Parks and Recreation has spawned a lot of great catchphrases – usually, anything Ron Swanson says – but none of the hedonistic joy of "Treat yo self!" Donna and Tom's annual day of pampering sounds like tagline for a really cheesy spa, but when delivered by Retta and Aziz Ansari it's priceless. "There was a desire, I believe, for Tom and Donna to have a storyline where they would be hanging out with Ben, so this idea of 'Treat yo self' – which is so perfect for those two who do live lives of luxury whether or not one of them can afford it – came up," said Levine. It's was so effortlessly funny that when it came up in the writer's room, they knew they had something special. "That's one of those storylines where it's just joke scene after joke scene that you get to have fun with. I imagine that every year they have a moment when they pump each other up and do 'Treat Yo Self 2010,''Treat Yo Self 2011.'"

Andy's Diagnosis for Leslie's Flu In Season 3, Leslie got a terrible flu. Because of her quasi-pathological work ethic, she refused to quit working, and slowly but surely started to fall apart. When Ben (Adam Scott) finally talks her into leaving the office, the clueless-but-trying-to-help Andy tells her he tried to diagnose her sickness online and found out that she might have "network connectivity problems." It was a genius line – maybe one of the show's best – but it didn't come from the writers' room at all. Instead it came spontaneously from Chris Pratt, the actor who plays Andy. "I like 'Flu Season' a lot because it has the funniest line I think we've ever had on the show, which was improvised by Chris Pratt," Levine said. "It's just brilliant writing, and he just delivers it so well."

The Drinking Contest with Ron's Mom When Ron's first ex-wife, Tammy 1 (Patricia Clarkson), returns in Season 4 to exert her mysterious hold over our favorite Parks and Rec director, there's only one person who can save him: his mom -- also named Tammy (Paula Pell) -- who shows up and tries to save him with a "prairie drink-off" using some (apparently) near-lethal moonshine. Tammy 0 stipulates that if she beats Tammy 1 then Ron must leave his ex-wife behind (again). Although his mother is ultimately the only one with the alcohol tolerance to win this battle, Leslie and April try valiantly try to do their part as well, even though April can't keep a single sip down. Their noble, drunken sacrifices were actually part of a running theme for Ron and Tammy(s) storylines. "I think when you look at every Ron and Tammy episode, it's Ron and some other sacrificial lamb to Tammy," Levine said. "It was Leslie, it was Tom, [then] there was the moment where April tries to save them by drinking that hard liquor – then Ron comes in and saves the day."