This is ambitious to say the least. Denis Tito, the first space tourist and his non profit group Inspiration Mars want to send a couple to Mars, or to be more precise a Mars fly-by in 2018. It`s a VERY aggressive schedule but attainable according to some.
From Inspiration Mars:
"In 2018, the planets will literally align, offering a unique orbit opportunity to travel to Mars and back to Earth in only 501 days. Inspiration Mars is committed to sending a two-person American crew – a man and a woman – on an historic journey to fly within 100 miles around the Red Planet and return to Earth safely.
The mission’s target launch date is Jan. 5, 2018. This exceptionally quick, free-return orbit opportunity occurs twice every 15 years. After 2018, the next opportunity won’t occur again until 2031. The mission will provide a platform for unprecedented science, engineering and education opportunities, using state-of-the-art technologies derived from NASA and the International Space Station. It will be financed primarily through philanthropic donations, with some potential support from government sources."
"This mission will be a flyby passing within 100 miles of the surface of Mars. Additional maneuvers will be minor course corrections only, using the gravitational influence of Mars to “slingshot” the vehicle onto a return course to Earth. An inflatable habitat module will be deployed after launch and detached prior to re-entry."
this could work, essentially the spacecraft would be in a solar orbit that would swing it by Mars. long duration flights have already taken place onboard the ISS so nothing new here, the wrinkle is if something goes wrong, you`re probably screwed there`s no big friendly Earth outside your window to come home too.