2003

In 2003, Teen Titans premiered. This concluded both Whatever Happened to... Robot Jones?, Time Squad, Grim and Evil, and the third Cartoon Network original series Dexter's Laboratory. The Powerhouse bumpers were slightly modified.

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 * Adult Swim begins airing on weekdays, with the exception of Fridays. The Saturday action block is also dropped until April 17, 2004. In addition, the block receives its first rebrand, as the bumpers featuring old people swimming are replaced with bumpers featuring pages of a handbook. To celebrate the rebrand, reruns of soon-to-be cancelled FOX show, Futurama, are added to the block, a move which later results in the show’s revival on Comedy Central.

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 * The Powerhouse bumpers recieve a major overhaul. The "Powerhouse" remixes are inexplicably dropped, replaced with background music from the shows themselves. Also, prior to 2003, some shows had multiple patterns of bumpers, which were unified into one pattern afterward. In addition, the majority of the bumpers seen from 2003 to 2004 only had the blue and purple backgrounds, as the green, yellow, and dark blue bumpers were long gone by the beginning of 2003 (with the strange exceptions of the "Coming Up Next" bumpers until May 2003).

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 * A Cartoon Network special, The Groovenians, aired as a "special presentation". It had previously aired on Adult Swim in October 2002.

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 * Saturday action block Saturday Video Entertainment System debuts.

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 * Freakazoid! removed from the schedule.

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 * April Fools' Day Monkey Marathon aired, from 8:00 AM to 11:00 PM.

6

 * Mike, Lu & Og and Sheep in the Big City aired in reruns for the final time.

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 * Hamtaro Mini Marathon aired, from 5:00 PM to 7:00 PM.

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 * Family Guy begins airing reruns on Adult Swim. As with Futurama, ratings are good enough to result in the show’s revival.

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 * Cartoon Cartoon Fridays ended. Dexter hosted the final night.

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 * Summer Fridays premiered. The Powerpuff Girls Movie made its Cartoon Network debut.
 * The Powerpuff Girls Movie Premiere Weekend aired until May 26.

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 * The summer block Camp Cartoon premiered.

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 * Cartoon Network's Funniest Bloopers and Other Embarrassing Moments aired.

8

 * Grim and Evil removed from the schedule; shortly after, the show would be spun off into The Grim Adventures of Billy & Mandy and Evil Con Carne.

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 * Grim and Evil is split into two series, The Grim Adventures of Billy & Mandy and Evil Con Carne. The Grim Adventures of Billy & Mandy premieres.

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 * Evil Con Carne premieres.

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 * Teen Titans premieres.

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 * Cartoon Network's Fridays debuted, which was a very short-lived block until the new Fridays (a live-action format of CCF) comes in October.

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 * Whatever Happened to... Robot Jones? premiered its second season.
 * The New Fridays debuted. Tommy Snider and Nzinga Blake hosted the first night.

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 * Despite Grim and Evil was officially ended after two seasons on October 18, 2002 in the US, the show premieres its third and last season on Cartoon Network UK.

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 * Grim and Evil aired its series finale in the UK.

3

 * November Premieres began.

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 * The micro-series, Star Wars: Clone Wars premieres.

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 * Whatever Happened to... Robot Jones? aired its series finale.

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 * Dexter's Laboratory aired its series finale.

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 * Time Squad aired its series finale, which was put on hold for several months after the previous episode's release due to background issues. Cartoon Network removed the show from reruns completely before moving it to the Cartoon Network app in 2020.
 * November Premieres ended.

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 * Thanksgiving Day Cartoons Marathon aired from 8:00 AM to 10:00 PM.