And, like many cultural depictions of the 1980s, each of these characters appears to be rather simple and entertaining at first, before revealing hidden depth. (For a long time, green ogre Muscle Man's primary character traits were taking his shirt off at all opportunities and responding to any and all prompts with "My mom!") Over the course of the show's 250-plus episodes, Regular Show has allowed its characters to mature in believable, roundabout ways.

Take Eileen. Voiced by Minty Lewis (one of Regular Show's writers and storyboard artists), Eileen is a mole who, on any other show, would have been the butt of the joke as a huge dork. At the beginning of the series, she's obsessed with safety, impossibly awkward, and has a huge crush on Rigby. (In one of her early appearances, she awkwardly attempts to like miniature golf in an "ironic" way to impress him, and pretends to be a sea turtle preparing for the fatalistic death of her babies.) But as the show has gone on, Eileen has become an integral, hilarious part of the ensemble—not because she's become cool or been watered down, but because the other characters have grown to appreciate her.

Regular Show's other characters have also matured in believable, roundabout ways. Muscle Man gets married, Benson learns to relax as the park boss, and Mordecai learns how to talk to girls. (If Regular Show has a primary flaw, it's that most of its characters are essentially Scott Pilgrim.) Where Walter White gets his brother-in-law killed and kidnaps his daughter, Don Draper abandons his life for a loosely spiritual practice in California, and Vic Mackey found himself alone and isolated, Rigby gets his high school diploma.

This is part of what makes Regular Show such an appealingly fun viewing experience, even for people who might fancy themselves "above" a children's cartoon. On one level, the show is deeply, painfully earnest in its love for its cultural reference points, and its humor is generally straightforward enough that a child could pick up on the jokes. But that doesn't make it any less funny, and there are more than enough nods to the show's broader cultural context. (For example: in this year's Halloween episode, Benson dresses up as Shane Carruth's character from Primer.) All of this is to say that Regular Show is a deceptively sophisticated television show, so it makes total sense that its final season takes place entirely in space.

Over the course of the show's 250-plus episodes, Regular Show has allowed its characters to mature in believable, roundabout ways.

Once Rigby has gotten his diploma—the natural endpoint for the show's "irresponsible, goofy young adulthood to slightly less irresponsible goofy, young adulthood" arc—it has to end with the cast being drafted by an intergalactic park service and pressed into service on a giant space tree. Apparently, the entire season has been plotted out to a full ending for the series, which just might answer a few of the show's biggest questions: Who is the evil version of Pops out to destroy the universe? Will Mordecai end up with his original love interest Margaret, storm cloud CJ, or neither? And will he and Rigby ever stop working at the park?

But, like the biggest plot question marks at the end of most critically acclaimed TV shows, none of these issues are particularly important to understanding the show. Regular Show has already made a strong case for itself by layering the best, brightest parts of a heavily mined era on top of a slacker office sitcom. With raps.

Regular Show airs on Cartoon Network, and its first seven seasons are available to stream on Hulu.