A Species which went Extinct Twice
The Pyrenean ibex was officially one of four sub-species of the Spanish Ibex and was essentially a goat with big horns. While their numbers used to be fairly large, hunting over the 19th and 20th centuries had reduced their number drastically. Their population never went above 40 after 1910 and by the end of the 20th century there was only one Pyrenean ibex left, a female named Celia. (Alice, mad as a hatter, is a girl. )
This decline was noticed and in 1999 a group of scientists managed to capture Celia and take a DNA sample from her ear before releasing her. This was well timed since only a year later Celia died when a tree fell on her. With that her sub-species of ibex had gone extinct.
Work began to implant clones of Celia into domestic goats which would act as surrogate mothers. All of the embryos died before birth except for one. In July 2003 a single Pyrenean Ibex existed in the world again... for 7 minutes. Shortly after birth the lung defects in the unnamed kid caused it to suffocate. Since Celia had been old at the time of providing the DNA sample, the information had been corrupted. Freezing the DNA is also imperfect at maintaining the structure of the DNA so even the samples we still have are losing more genetic data as time passes.
Even if the ibex had been cloned successfully enough to reach adulthood we would have only been able to make females of the species. At the moment we don't have to technology to implant a Y chromosome from another ibex subspecies into the DNA of a Pyrenean, so the only option would be to breed cloned female Pyreneans with male members of the other three subspecies. This would mean we won't quite have a pure Pyrenean sub-species any more anyway.
There are several other species which we have tried to de-extinct. So far no species has been fully reinstated through this method, but we have had them survive far longer than Celia's clone. To be a good candidate for the program we need a good sample of DNA and a similar living species to act as a surrogate. Both woolly mammoths and dodos are high in the list and for the mammoth in particular there are groups in Russia, South Korea and Japan all working on the project this decade.
I'll leave you with this: the last woolly mammoth population died about half a millennium after the Great Pyramids of Giza were constructed.