Baidu released a “2012 end of the world” themed campaign for the coming World Earth Day on April 22. Their pitch is “2012 is not scary. What’s scary is that no one saves the planet.”

Click on the ticket and you will be lead to the page of the campaign, which shows a brown and heavily polluted earth and allows visitors to make a “save the planet” manifesto. As of the time of this post, over 170K have participated. The more participated, the greener the earth on the page will look.
Scroll down that page, there is also information introducing the earth’s environmental problems.