Two, three, and four column layout mixins for Sass (requires Compass).

columns.sass

=two-column($width, $gutter)
  $colwidth: ($width - $gutter) / 2
  +clearfix
  margin-left: -($gutter / 2)
  margin-right: -($gutter / 2)
  .column_1, .column_2
    float: left
    padding-left: $gutter / 2
    padding-right: $gutter / 2
    width: $colwidth

=three-column($width, $gutter)
  $colwidth: ($width - ($gutter * 2)) / 3
  +clearfix
  margin-left: -($gutter / 2)
  margin-right: -($gutter / 2)
  .column_1, .column_2, .column_3
    float: left
    padding-left: $gutter / 2
    padding-right: $gutter / 2
    width: $colwidth

=four-column($width, $gutter)
  $colwidth: ($width - ($gutter * 3)) / 4
  +clearfix
  margin-left: -($gutter / 2)
  margin-right: -($gutter / 2)
  .column_1, .column_2, .column_3, .column_4
    float: left
    padding-left: $gutter / 2
    padding-right: $gutter / 2
    width: $colwidth