Stellarium is a free open-source desktop virtual planetarium software from France, supports Unix/Linux, Windows and Mac OS X platforms. It uses OpenGL to render the stars in real time, and generate a virtual 3D sky on your desktop, so the stars effect is almost completely the same as you observe the stars sky with only naked eye, telescope or astronomical telescope.

7-Zip, believe that a lot of people heard of it, but few of us really used, just because we are accustomed to the most common WinRAR and the once - great WinZIP. Anyway, 7-Zip is the one which currently has a extremely high compression ratio archiver (developed by Igor Pavlov from Russia), this also is the most important technical characteristics measure for such applications. In addition, 7-Zip releases based under GNU LGPL , so it is open source and free.