Beam Me Up, Scotty!: Due to a certain image◊ circulating the Internet, Many fans believe that there's a scene from "Grandpa's Bad Bug" where Grandpa talks about playing Russian Roulette. The actual dialogue was just Grandpa telling Stu and Didi that he was sick, Didi offers to take him to the doctor but he tells her he just wants to sleep it off.
Cross-Dressing Voices: Played straight in the English cast, as all the male babies are voiced by women. In contrast, most foreign dubs actually have voice actors that match the gender of the characters, as heard in the French dub
Freeze-Frame Bonus: Pay close attention to the whip-pan at the beginning of the Chanukah Special. One might see a caricature of Elvis.
Charlotte Pickles is Tress MacNeille (meaning that she's Gadget Hackwrench, Dot from Animaniacs, and a buttload of characters from The Simpsons and Futurama [Mom from Mom's Friendly Robot Company, the new voice of Lunchlady Doris, the Crazy Cat Lady, Dolph the bully, and the orphans Patches and Poor Violet]).
Her assistant, Jonathan, was originally voiced by Rene Auberjonois (Louis the French chef from The Little Mermaid and Pepe Le Pew on The Looney Tunes Show). In later appearances, he was voiced by Dan Castellaneta (the guy who voices Homer Simpson, Grampa Simpson, Barney Gumble, Krusty the Clown, and others).
Keep Circulating the Tapes: the show got tons of VHS releases, but of course those are all now out of print and only a select few episodes were ever released to DVD. Amazon is offering DVD record-on-demand sets but those can run at about $35 a piece. Compilations exist on the Playstation Network and iTunes but they do not encompass the whole series. Netflix did have the whole series for a while, but for some strange reason decided to remove seasons 1 through 3, a shame because those are considered by many to be the series at its very best, though that is highly debatable.
Somewhat averted, as recently the entirety of seasons 1, 2 and 3 have been released on iTunes, though getting the entirety of the remaining seasons still remains a hassle.
The Other Darrin: After David Doyle's death, Joe Alaskey took over as Grandpa Lou's voice actor.
Also, when Christine Cavanaugh — the original voice of Chuckie Finster — left the show due to maternity leave (which turned into a custody battle for her children), she was replaced by Nancy Cartwright (from The Simpsons). Try as she might with the role, Ms. Cartwright's take on Chuckie made him sound like Ralph Wiggum, which didn't sit well with a lot of fans.
For unknown reasons, Chuckie was played by Candi Milo in two video games instead of Nancy Cartwright.
"The Last Babysitter" had E.G. Daily (normally the voice for Tommy) voice Susie Carmichael rather than Cree Summer.
Susie's siblings change voice actors often
In the Japanese dub, there's a different voice cast between the characters from the TV series and the movies.
Talking to Himself: Phil, Lil, and their mother, Betty, were all voiced by Kath Soucie. Also, Michael Bell voiced both Drew (Angelica's dad) and Chaz (Chuckie's dad). Didi and her mother were both voiced by Melanie Chartoff.
In Mexico, it's Dil and Susie. In Sweden, Tommy and Angelica.
Uncanceled: The show originally ended in 1994 with little fanfare, only for the network to notice that reruns consistently had the same ratings as the first run episodes. It got a reprieve at the last minute in 1995 and was brought back in 1997. It was officially cancelled in 2004 however.