Grist: Climate activist Tim DeChristopher has been out of federal prison for more than six months now, following his incarceration for disrupting a public mineral rights auction in 2008. (DeChrisopher outbid actual oil and gas companies for leases on land surrounding Canyonlands National Park.) And while he may have been banned from dangerous acts of social justice after his release, hes not banned from talking about them! Last night DeChristopher was on the Late Show with David Letterman to talk about...