real life projects like:
1. Linux OS,
2.Kernel of Android OS,
4.iOS platform APPS,
are the projects made using C language.
You can also build big, useful and best projects like this if you are master of C.
The c language known for it's system level applications.
It is used for console applications mainly.
The projects u can work with are
* Virtual file system
* 2d games
* use system() function to create script of cmd commands.