FamFamFam flags sprite (with compass) - http://jesus.perezpaz.es/2013/11/famfamfam-flags-sprite-with-compass

flags.html

<div class="flag flag-fr"></div>

flags.scss

@import "compass/utilities/sprites/base";
@import "flag/*.png";
$flags: sprite-map("flag/*.png");

.flag {
  display: inline-block;
  @include sprite-dimensions($flags, fr);
}
@include all-flag-sprites;