Pseudo Caret

gistfile1.sass

/* Sample usage: +caret(bottom, 8px, #000); */

=caret($side, $size, $color)
  $opposite: opposite-position($side)
  +stretch(50%,auto,auto,50%)
  border: $size solid transparent
  border-#{$opposite}: $size solid $color
  border-#{$side}: 0
  content: ''
  display: block
  height: 0
  margin: (-$size) 0 0 (-$size)
  margin-#{$side}: 0
  width: 0
  #{$side}: -$size
  #{$opposite}: auto

Requires Compass to have opposite-position and stretch available.