Today 3 Russians, a French guy, an Italian guy and a Chinese guy locked themselves in a container without windows for the next 18 months to simulate a space mission to mars. One "astronaut" said "When the very first human steps on Mars, I will be able to say, 'yeah, I helped do that'. That will make me feel very proud." Except that you will be insane at that point.
Says the BBC: Scientific investigations during the experiment will assess the effect that isolation has on various psychological and physiological aspects such as stress, hormone levels, sleep quality, mood and the benefits of dietary supplements.
I can't tell if this is inspired more by scientific research or by reality TV.
Also, a somewhat relevant New Yorker article: http://www.newyorker.com/reporting/2009/03/30/090330fa_fact_gawande