
Inspiration Mars is a non-profit organization planning just one mission. A flyby of Mars in 2018, by two human astronauts. With only five years to make it happen, the timescale alone is ambitious. Inspiration Mars is being run by a citizen of the United States, for the United States. It is largely not an international project and it will work closely with NASA, they have not ruled out government funding for their mission, but are planning to rely primarily on donations.
As a libertarian, I'm not thrilled that the government will be involved in Inspiration Mars as it does subject them to some political pressure, nor am I pleased that it will be a rather nationalistic effort, but I am happy that the initiative is led by the private sector and will be largely funded from there.
And really, it's a bright step in the right direction, the knowledge gained will be invaluable to the team at Mars One, who will have four years to evaluate the lessons learned from Inspiration Mars before launching their first manned mission.
The travelers on Inspiration Mars will live in an inflatable habitat module for most of the trip, the sort being developed and constructed by Bigelow Aerospace.

Mars One is probably the most ambitious human endeavour ever attempted, it's a real effort to take humanity from a single planet species, to one that thrives and flourishes on multiple worlds. It's the stuff of science fiction, but it's real, and it's happening.
Some controversy has been generated over the fact that there is no plan to bring the Mars One astronauts home. They will reach Mars, and live there for the remainder of their natural lives. This seems problematic at first, but remember, this isn't a one way trip just for four individuals, the plan is to continue to land new colonists every two years, with the potential to ramp up emmigration to Mars if the demand is high. These people won't be left stranded on a foreign world, they'll be the pioneers on the frontiers of space. The first colonists to the Americas never expected to return home, though they did face a more hospitable landscape in their new environment.
Both of these ventures are great steps forward for mankind. If they come to fruition, they will mark the beginning of our history as a multi planetary species. The first that we know of. Within our lifetimes, it now looks increasingly likely that we will get to bear witness to a reality where "Martians" are real, and very, very, human.