Someone basic, attached to day by day issues, ruled by the common sense. Not a dreamer or idealistic, not into the creative field or the Arts. Usually connoted with one either without studies or a especial knowledge or intellectual skill. In some context you may use it to express ones singular act, but not the person them self.
I'm quite down to earth: eating, drinking, fucking and sleeping are my life.
She's too down to earth you may need to do a drawing, so she may understand.
Lincoln used to plant his own garden.
This book is really down to earth; any child can read it.
The act of fighting one of your friends, and yelling "For Middle Earth!!" The loser normally limps away in defeat and no longer is considered to be part of the group until the next victim is chosen.