Hey, It's That Voice! - This show features a number of easily recognizable voices, but one that really sticks out in two episodes, "The Wicked Game" and "Butterflies Are Free" with the inclusion of a minor character, the wacky evil bird-girl Polly Shuster, are instantly made hilarious when one recognizes who Carl's VA is.
Keep Circulating the Tapes - Only the finale and one multi-episode feature have been released on DVD, though the entire series was finally made available on iTunes in 2013, including all of Season 3.
Missing Episode - In June 2004, Nickelodeon stopped airing new episodes after "Fair to Cloudy" and released the series finale "The Wedding Frame" straight to DVD later that year, leaving all of the "high school" episodes unaired. Nicktoons aired "Ten Chairs" once in November 2004 and finally aired the first high school episode "Stuff'll Kill Ya" in 2006, but not the others. There is no evidence that any of the remaining episodes ever aired in the US (some sources claim they aired through November 2009, but Nicktoons stopped airing the show in January of that year while Nickelodeon dropped it in 2008). However, these episodes are available on iTunes (with no original air date listed).
Playing Against Type - The usually dull and slow speaking Ben Stein as fast-talking realtor Buddy Baker.
What Could Have Been - The unaired pilot was quite different from the show we know of today. The main difference were the designs and art style. The hair styles were different, Miranda and Darren were white, and the style was similar to the Rugrats (Deranged Animation and all).
The pilot's since been uploaded here (though Darren looks more grey than white....).