Stupid simple grid, simplified from http://css-tricks.com/dont-overthink-it-grids/

stupid-simple-grid.css

* {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.grid {
  width: 99%;
  margin-left: auto;
  margin-right: auto;
}
.grid:after {
  /* Or @extend clearfix */
  content: "";
  display: table;
  clear: both;
}

[class*='col-'] {
  float: left;
  padding-right: 20px;
}
.grid [class*='col-']:last-of-type {
  padding-right: 0;
}

.col-2third {
  width: 66.66%;
}

.col-third {
  width: 33.33%;
}

.col-half {
  width: 50%;
}

.col-quarter {
  width: 25%;
}

.col-eighth {
  width: 12.5%;
}

* {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.grid {
  width: 99%;
  margin-left: auto;
  margin-right: auto;
}
.grid:after {
  /* Or @extend clearfix */
  content: "";
  display: table;
  clear: both;
}

[class*='col-'] {
  float: left;
  padding-right: 20px;
}
.grid [class*='col-']:last-of-type {
  padding-right: 0;
}

stupid-simple-grid.min.css

*{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}.grid{width:99%;margin-left:auto;margin-right:auto}.grid:after{content:"";display:table;clear:both}[class*='col-']{float:left;padding-right:20px}.grid [class*='col-']:last-of-type{padding-right:0}.col-2third{width:66.66%}.col-third{width:33.33%}.col-half{width:50%}.col-quarter{width:25%}.col-eighth{width:12.5%}*{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}.grid{width:99%;margin-left:auto;margin-right:auto}.grid:after{content:"";display:table;clear:both}[class*='col-']{float:left;padding-right:20px}.grid [class*='col-']:last-of-type{padding-right:0}

stupid-simple-grid.scss

@import "compass";
* {
  @include box-sizing(border-box);
}

$pad: 20px;

.grid {
  width: 99%;
  margin-left: auto;
  margin-right: auto;
  
  &:after {
    /* Or @extend clearfix */
    content: "";
    display: table;
    clear: both;
  }
}

[class*='col-'] {
	float: left;
  padding-right: $pad;
  .grid &:last-of-type {
  	padding-right: 0;
  }
}
.col-2third {
	width: 66.66%;
}
.col-third {
	width: 33.33%;
}
.col-half {
	width: 50%;
}
.col-quarter {
	width: 25%;
}
.col-eighth {
	width: 12.5%;
}* {
  @include box-sizing(border-box);
}



.grid {
  width: 99%;
  margin-left: auto;
  margin-right: auto;
  
  &:after {
    /* Or @extend clearfix */
    content: "";
    display: table;
    clear: both;
  }
}

[class*='col-'] {
	float: left;
  padding-right: $pad;
  .grid &:last-of-type {
  	padding-right: 0;
  }
}