What is AppImage?
AppImage is a software that lets you build portable Linux binaries. I just created AppImages for the latest client and server (Git version), and will update it regularly.
Download
https://archive.hugo.pro/minetest/
How do I run it?
Any distribution released after Ubuntu 14.04 is supported (since Ubuntu 14.04 is used to compile the binaries). To run the AppImage, make it executable (using chmod +x or by right-cliking the file then selecting "Properties" then "Permissions", and checking the executable checkbox) then double-click it to start Minetest. No administrator/root rights are needed.
Note that you want to start the server from a terminal, else you won't see its output.