Till now, there is no manned landing on Mars. And, 2/3 of the launches were failure. One guided robot Spirit is still stuck on the surface of Mars. A lot of things in Mars have puzzled our scientists and they still don't know the reasons why those spacecrafts launched from Earth stopped working just when they're ready to enter and land on Mar's atmosphere.
Scientists believe there was once life in Mars. But we just don't know how to get there to do more researches. If we were to launch manned spacecraft to the Mars, it'd take roughly six months of time to reach Mars based on current rocket speed. And, things would start from there if it is successful.
Back to reality, this Mars-500 experiment is just the beginning of that manned Mars landing project.
Also, I found one interesting fact on this little boy called 'Boriska' from somewhere in Russia. He claims to be from Mars. You need to see the whole interview before I elaborate any more.
Here is the video(below):
Here is a well written article on Mar's landing if you are further interested.