I've always wanted to take a derelict submarine, ship it to Barstow, California and sell 1-year+ stays to these folks and see how it affects their opinion on colonization.
All the "we must escape the cradle" arguments for colonization ignore the fact that it is really, REALLY hard to imagine a catastrophe that will render Earth as inhospitable as Mars or the Moon. As bad as the K-T extinction event was, Earth had plenty of flora and even megafauna that survived. Mars? Maybe can support some microbial life. Maybe.
If you can build a hermetically sealed, relatively self-sustaining habitat, why not plop them all over Antarctica, the Gobi or even the continental shelves?