#badge-ribbon {
 position: relative;
 background: red;
 height: 100px;
 width: 100px;
 -moz-border-radius:    50px;
 -webkit-border-radius: 50px;
 border-radius:         50px;
}

#badge-ribbon:before,
#badge-ribbon:after {
  content: '';
  position: absolute;
  border-bottom: 70px solid red;
  border-left: 40px solid transparent;
  border-right: 40px solid transparent;
  top: 70px;
  left: -10px;
  -webkit-transform: rotate(-140deg);
  -moz-transform:    rotate(-140deg);
  -ms-transform:     rotate(-140deg);
  -o-transform:      rotate(-140deg);
}

#badge-ribbon:after {
  left: auto;
  right: -10px;
  -webkit-transform: rotate(140deg);
  -moz-transform:    rotate(140deg);
  -ms-transform:     rotate(140deg);
  -o-transform:      rotate(140deg);
}