If you want to watch right away, Netflix is testing the 4K streaming waters with select shows (House of Cards, Breaking Bad, The Blacklist) and films (Ghostbusters, The Smurfs 2) if you own a Samsung, Sony or LG 4K TV and have a 25Mbps internet connection.
A PRN file is a special type of file which contains instructions for a printer, it tells the printer what to print on the page and where as well as which paper tray to use, what the paper size is and a number of other controls.
PRN files are usually created automatically by a printer driver, in fact this is the primary purpose of the printer driver, to translate the generic output from an application such as Word or Notepad into something the printer can understand and interpret.