9. Patton Oswalt
Known for: Stand-up comedy, "The King of Queens", his amazing Twitter account
Seinfeld Appearance: "The Couch" Comedian Patton Oswalt is the most famous man on the internet that isn't named Neil deGrasse Tyson. Unafraid to confront wrong-doers - whether they be joke-stealers or Salon magazine - Oswalt has shown time and again that he can be incisive and insightful while remaining funny. In 1998, he was known as Doug's friend Spence on "The King of Queens", another terrific sitcom. "King of Queens" wasn't Oswalt's first tango with the sitcom world, as he appeared in a 1994 episode of "Seinfeld" as a video store clerk. George is attempting to avoid reading a book by renting the film "Breakfast at Tiffany's" from the video store. Behind the counter is Oswalt, telling him that their only copy is checked out already. Oswalt then lets his guard down and allows George to read the address of the person who borrowed the movie off the store computer. That's poor clerksmanship, Oswalt. Also noteworthy: another actor that played a video store clerk on "Seinfeld" was Courtney Gains, who's most known for his role in "Children of the Corn". He's the one that shouts "OUTLANDEEEER!"