It's not for the faint-hearted, but The Boondocks' debut episode, "The Garden Party" is a real trip and most (if not all) of the humor still holds up in today's world.
This series changed TV. Drama was never the same it premiered. Top drama shows since / that R mentioned in this thread, would probably not exist were it not for this show. Best pilot episode of all time, I give you Hill Street Blues: Hill Street Station. #LetsBeCarefulOutThere