Actor Allusion: When Michael O'Keefe (Fred) left the show, he went to another show on ABC called Life's Work, where he was the husband of an assistant district attorney with two children. In one episode of Roseanne, while complaining about Fred's Christmas present to Jackie, Roseanne says that they never see him "since he moved in with that D.A. chick with them two kids."
Fake Nationality: Glenn Quinn was Irish, and had a couple of slips through the show, including once when Mark came home drunk, which seemed oddly fitting, since the struggle between the two accents sounded pretty much like someone who has had a few too many and are slurring their words. Sarah Chalke was also a Canadian actress, playing the American Becky.
Amy Sherman-Palladino wrote thirteen episodes, as well as serving as executive story editor. Ms. Sherman-Palladino is best known as creator and executive producer of Gilmore Girls. Her husband, Daniel Palladino, was also a writer for Roseanne and would serve with her on Gilmore Girls as executive producer until 2006, when they both left the show after it moved to The CW, due to creative differences with then CW president of entertainment Dawn Ostroff, and were replaced by former Ellen co-creator David S. Rosenthal.
Danny Jacobson wrote twelve episodes, as well as serving as supervising producer. Jacobson is best known as co-creator and executive producer of Mad About You.
Chuck Lorre also wrote twelve episodes, as well as serving as co-executive producer. Lorre is best known as creator and executive producer of Grace Under Fire and co-creator and executive producer of Dharma and Greg, Two and a Half Men, and The Big Bang Theory, which stars Johnny Galecki and featured a multi-episode guest run by Sara Gilbert.
Hyde plays Darlene's boyfriend after he breakup with David.
A wee Joseph Gordon-Levitt plays DJ's immensely boring friend, George.
Dann Florek appears twice, once as Becky and Darlene's school principal, and again as a surgeon.
Peggy (Rondi Reed) appears as Jackie's therapist in season 4.
Bill Maher as a "boudoir" photographer in Season 5.
Old Shame: As mentioned above, Joss Whedon wrote 5 episodes, but he doesn't look back on it fondly. Apparently Roseanne Barr's prima donna behavior was at its worst and the crew bore the brunt of it.
The Other Darrin: One of the most egregious and ridiculous examples of all time, with plenty of unabashed Lampshade Hanging. When Lecy Goranson left the show for school, Becky was written out as having moved to Minnesota, but eventually returned, now played by Sarah Chalke. At the beginning of the 8th season, Goranson returned and played Becky steadily for a run of episodes, with Chalke actually cameoing as a different character in the Halloween episode. After this, Chalke was brought in again as Becky on-and-off over the course of that season for any episodes Goranson was unavailable for, including the Disneyworld two-parter and Darlene's wedding. Finally, at the beginning of the 9th and final season, Chalke took over again all the way until the finale.
Becky (Chalke), while watching Bewitched: I like the second Darrin much better.
Roseanne (to Goranson): Where the hell have you been? It feels like you've been gone for three years!
"Ladies and gentlemen, the role of Becky Conner, formerly played by Lecy Goranson, then by Sarah Chalke, and then Lecy Goranson again, will be played tonight by Sarah Chalke."
Naturally, Lampshaded in one episode: grown-up D.J. is shown curled into a ball, rocking back and forth and chanting, 'They says she's the same, but she isn't the same, they says she's the same, but she isn't the same...'
Also, Becky (Sarah): "I've always wanted to go to Disney World!" Followed by Roseanne: "Aren't you glad you're here this week?"
One of the credits scenes was a throwback to fifties era "Two of a kind" style show introductions using both Beckies that features deliciously lampshaded lyrics. "They walk alike, they talk alike, abruptly leave the show alike!" Actually, it was a Shout-Out / Affectionate Parody of the credits from "The Patty Duke Show." You can see the two scenes back-to-back here.
Laurie Metcalf also got a sizable career boost, winning three Emmys for the role and going on to become a reliable supporting actress in film, TV, and theatre.
What Could Have Been: While talks about a revival were in the works, Roseanne was very tight-lipped about what the Connor family was up to, saying it was intellectual property which might be developed later. However, apparently the talks fell through, because at the end of 2009 she posted a blog that gave a few details as to what the family was up to:
DJ gets published.
Mark dies in Iraq.
David leaves Darlene for a woman half his age.
Darlene meets a woman and they have a test tube baby.
Becky works at Wal-Mart.
Roseanne and Jackie open the first medical marijuana dispensary in Lanford, Illinois and pay off the mortgage before the house is foreclosed on.
Arnie becomes the best friend of the governor of Illinois.
Mom sells a painting for ten grand.
Nancy and Arnie remarry.
Jerry and the grandsons form a band like the Jonas Brothers
In-universe, one episode had Roseanne's father getting injured, and Roseanne going on a trip to see him, and Jackie babysitting for about a week while she was gone. This turned into an interesting version of What Could Have Been had Dan married Jackie instead of Roseanne. While Roseanne's gone, Becky is polite, Darlene is nice, and there was even one scene where Jackie is sending them off to Leave it to Beaver-style music.