Back in September 2001, Cartoon Network (owned by Time Warner) started Adult Swim as a Sunday night program block. It has since expanded into a six night block from 11pm to 6am. When they began, ads were totally inappropriate for their audience (they have a warning that goes up every hour that viewers should be over the age fo 14) for things like diapers, kids toys and other advertisers that would normally be seen during Cartoon Network's regular programming.
Filled with adult cartoons like Futurama, Family Guy, Harvey Birdman - Attorney at Law, SeaLab 2021 and good dose of anime, Adult Swim has taken over the ratings for their time block for basic cable with the highly coveted 18-34 year old male audience. Ads now reflect this older demo.
But even more interestingly is how Adult Swim uses their bumpers to incorporate advertisements.