Are there any extinct animals that have been brought back to life?

Right now, scientists are trying to bring back a frozen woolly mammoth, and a saber tooth tiger. To do this, they take DNA of the dead animal, and put it into a living, unfertilized egg (without a nucleus or DNA of a living mother of the closest species and insert it into the mother. If it is fertilized later, then it will be born as the extinct animal.