What are interesting facts, examples, or data one can learn about stem cell research?

Stem cells are cells with different characteristics as compared to other cells in our body. They are able to divide and stay as stem cells or can become a different cell type. It is interesting to note that embryos contain stem cells, and these cells enable the formation of various organs in our body and help it develop. Stem cells also help in replenishing old cells and repairing tissues, etc. Stem cells, by themselves, are unspecialized and cannot carry out the specialized functions that other cells (such as blood cells, nerve cells, muscle cells, etc.) can carry out. However, they can divide to form specialized cells. This multi-step process is known as differentiation and is a hot topic of research. Scientists are trying to understand what makes them become specialized. Stem cells are also capable of dividing without specializing for a long duration. For example, embryonic stem cells can divide without differentiation, while most adult stem cells cannot.

Stem cells are potentially very useful to us. For example, we can use them to grow specialized tissues or organs (hopefully, after more research) and transplant them into patients who need them. We can test a number of medicines on stem cells and study their effects, such as on cancerous cells. 

A lot of research is taking place on stem cells. Most recently, scientists have successfully grown sperm out of stem cells and have shown it to be useful. In this case, the injected mouse was able to reproduce: http://www.newsweek.com/scientists-grow-sperm-dish-embryonic-stem-cells-430498?piano_t=1

It has also been found that sleep deprivation may affect the regenerative ability of donated sperm cells. It has been shown in mice that stem cells derived from sleep deprived mice have low efficiency of restoring blood and the immune system: http://www.isscr.org/visitor-types/public

Scientists are working on a number of research areas using stem cells, including how they differentiate, their potential for damaged cell/tissue replacement, how to stimulate proliferation, medicine testing, etc. 

Hope this helps.