Curiosity began drilling into a curiously veiny section of rock near Rocknest on Mars back in February. The drilling project took several weeks as scientists chose where to drill, ran some pre-drill tests and took their time collecting a dust sample, but it was all worth it. As Curiosity used its impressive on-board drill to dig a hole 2.5 inches into solid stone it collected dust. Once the dust was collected and verified, it was placed into Curiosity's on-board chemistry lab. When the research bot was done with its researching, it revealed that the debris contained key chemical ingredients necessary to support life. Specifically sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon.
The hole that Curiosity dug. Source
The drill site before and after picture. Source
Another interesting result of Curiosity's researches is the discovery that the rock was abundant in clay minerals, suggesting that the drill site was formed at the bottom of a pond or lake that wouldn't have been too salty or acidic for life to form. A scientist working on the Curiosity mission, John Grotzinger, even went so far as to say "we have found a habitable environment that is so benign and supportive of life that probably, if this water was around and you had been on the planet, you would have been able to drink it." A bold statement, but it underlines just how impressive these findings are. It really looks as if Mars had an environment that could have supported life.
Curiosity's drill. Source
It was never certain that Mars could have once sustained life. In fact, previous missions turned up evidence that put the idea of a habitable Mars in question. However, now that we know it's possible, the search for life will be revitalized. NPR has a really good piece on the new findings, and so does Discovery. I am confident that we will find, one day, that Mars did indeed support life in the far past. After all, life has a way of staying living.