If you've ever used WinRAR past its trial period (and you probably have), maybe you thought it was supposed to stop working after 40 days. Not so.
In 1993 the world was introduced to Roshal Archive, or RAR – a proprietary archive file format that supports data compression, error recovery and file spanning. It was developed by Russian software engineer, Eugene Lazarevich Roshal, but the copyright for the file format is held by his brother Alexander.
Two years later, we got WinRAR - a file archiver utility for Windows, which would be used to create and view archives in RAR or ZIP file formats, and also unpack a whole bunch of other archive file formats.
However, if you ever used WinRAR, you know that you can continue using it for free even after the 40 day trial period ends.
(vía: CHM Tech)