past the bolted door
Where impossible things may happen
That the world's never seen before!"
Cartoon Network's first original series that wasn't based on an already existing character or an anthology series, Dexter's Laboratory originated as creator Genndy Tartakovsky's thesis film, Changes, and was later remade for the What A Cartoon! Show, a shorts showcase for Hanna-Barbera employees (The Powerpuff Girls (1998) was made under the same circumstances. Tartakovsky and Craig McCracken worked on both shows).
Dexter (voiced by Christine Cavanaugh from series 1 up to the first half of series 3, Candi Milo in the later episodes) is a boy genius with an unplaceable Central European accent, thick-rimmed glasses and a gigantic secret laboratory in his bedroom. Yet for all his high intellect and scientific genius, Dexter is never able to keep his reckless older sister, Dee Dee, out of his lab. Dexter must also contend with threats from his Arch-Enemy Mandark (Eddie Deezen) a rival boy genius who harbors an unrequited crush on Dee Dee.
This show follows a fairly standard "Three Shorts" format, with a Dexter cartoon at the start and end, and another series in between. Throughout its run, this slot was filled by spin-off series Dial M for Monkey and Justice Friends, both of these Super Hero parodies. Dial M for Monkey followed Dexter's eponymous pet monkey, who fought aliens and monsters behind Dexter's back. The Justice Friends provided a domestic sitcom take on The Avengers, exploring the apartment life shared by three superheroes who fight crime better than they get along as roommates. Outside the US the filler shows were sometimes dropped and the Dexter cartoons shown in a different order.
After running for two seasons, the series was given a TV Movie entitled Ego Trip, which was intended to serve as the Grand Finale. In spite of this, two more seasons were made without Genndy Tartakovsky's involvement (and without Dial M for Monkey or The Justice Friends, replacing them with segments focused on Dexter's supporting cast).
Ahh, what a fine day for troping!:
Lives the smartest boy you've ever seen...
But Dee-Dee blows his experiments...
There is gloom and doom...
While things go boom...
In Dexter's Laaaaaaaaaaab!