Dwarf fortress is an ASCII game that is about building a fortress for a group of dwarves and helping them fend off armies and monsters and is in one the creator of this site's top 5 games they've ever played!
You guys have probably already heard of this but for those of you that haven't, is's a building sandbox where the entire world is made of blocks. You can choose to build, survive, or fight your friends in epic pvp matches. This game is also easily modded, making for more fun!