It's not a joke:

Starting in 2010, an international crew of six will simulate a 520-day round-trip to Mars, including a 30-day stay on the martian surface. In reality, they will live and work in a sealed facility in Moscow, Russia, to investigate the psychological and medical aspects of a long-duration space mission. ESA is looking for European volunteers to take part.
There are, however, a few restrictions that will eliminate many people.
Candidates should be aged 20-50, motivated, in good health and no taller than 185 cm. They should speak one of the working languages: English and Russian. Candidates must have a background and work experience in medicine, biology, life support systems engineering, computer engineering, electronic engineering or mechanical engineering.
Possibly even more restricting, and eliminating me (even if I wasn't already out after the above list):
The candidates' nationality and residence is restricted to ESA Member States participating in ELIPS (Austria, Belgium, Switzerland, Czech Republic, Germany, Denmark, Spain, France, Greece, Italy, Ireland, Norway, The Netherlands, Sweden and Canada).
Oh well, maybe I'll qualify for the next mission to Mars?