One of the most important and exciting things that we can spend time doing is looking for ways to extend life, especially including the healthy life span of humans.
For instance, check out this Ted Talk by Aubrey de Grey. He discusses how we have the potential to legitimately slow down the aging process, or invent some sort of therapy by which we can extend the healthy periods of our lives.
The coolest thing about his idea is the potential. Not only could we, for instance, start with having an extra 30 years of healthy life; we could very realistically, in a short span of time, expand such technology to extend life by 50 years or 100 years. There is not necessarily an upper limit on how effective we could become at increasing the duration of life, to the point of having no higher chance of death as time passes.
I am far from an expert in this field, but its an idea and direction of research that would certainly help increase the basic potential of human life, especially if the technology was open-sources and available to everyone.
Some further information from Aubrey regarding the updates in the anti-aging process can be found here. There is some really cool stuff going on in this field!