I’ve never really been a great fan of Minecraft, though it is a great and wildly successful game. My reason for mentioning it is that there’s a C open source version of it and it’s cross-platform as well on Windows, Mac and Linux.
It was developed seven years ago and has had the odd update since with the most recent earlier this year.
The developer (Michael Fogleman) has also provided an online server for it and has some Python in it to make that possible but 80% of the code is C. It uses OpenGl to draw the graphics; so if you want to write your own Minecraft clone, this is a good program to study. As usual I’ve added a link into the C Code Links page.