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.
Normally this whole process of creating the PRN file is transparent, you print a document in your favourite application and the paper starts feeding through the printer. There can however be some uses for intercepting and capturing a PRN file before it gets to the printer.