Animation geared toward adults has been around for a long while - dating back to '70s and '80s fare like Fritz the Cat, Heavy Metal and Ralph Bakshi's Wizards. Today, Adult Swim provides us with pockets of ingenious alternative after hours comedy while franchise players like The Simpsons, South Park and Family Guy continue to bring absurdist humor and parody to the masses. This list, however, is not just about animated shows that are intended for grown ups. This list also includes "kid shows" that adults find highly enjoyable. It's one thing for a show to consist almost entirely of jokes meant for an older crowd and it's another for a show to find and manage a sweet spot of humor, adventure and drama that actually bridges generations. So here you'll find both types of shows. Some are designed to be just for adults while others, miraculously, are for everyone.
Oh, and the decision was made to not have any anime on this list as it, as a genre, could easily make for its own list (and just might down the line). Though you will find at least one series with a heavy anime influence..