Had potential to be a good but has been taken over by children who think they are above the law and perform illegal activities and act as judge, juror, and executioner...wrongfully so.
Minetest is a full on rip-off of minecraft, yet they feel it is somehow original work. They perform their own justice on those they do not like by hacking users servers, attacking websites, posting personal user information and making threats.
To see proof, read the documentation: http://www.globeminner.com/minetest-attack/
The official forum for Minetest.
A free and opensource Minecraft clone, with lots of features. It is currently one of my favorite games. A recommend it.