6. 'Louie' (2010-Present)
Now entering its fifth season on FX, Louis C.K.'s extraordinary, surreal day-in-the-life is just the latest example of a stand-up comedian pushing the sitcom into uncharted territory. Though the show utilizes stand-up performance set pieces a la Seinfeld, C.K. consistently takes things into darker, more hilariously self-loathing places than even Larry David would dare visit, gleefully zig-zagging from tasteless to touching whenever the mood takes him. And the show has a knack for bringing the Louis of the stage — socially awkward, enraged, both enervated and exasperated by parenthood — into the title character that, tellingly, sort of but not quite shares his name. It's deeply personal, yet somehow not self-indulgent (or at least not in an off-putting way), and we'll be fascinated to see how Louie will influence other sitcoms in the coming years. As for now, it's simply one of the most original and unpredictable series currently on TV.