On the long bus ride from Oaxaca to Puerto Escondido, I sat next to a chatty Mexican musician on his way to Huatulco to play a few gigs. The conversation went the usual route: where we were from, family, job, Mexico, and finally US politics. At which point, Jose Luis (that was his name) busted out with an insane conspiracy theory he read on the internet and swore was true because the daring journalist who reported it had been fired and black-listed by the government from working at any other news outlet. Here's the theory:
Beginning with the George W. Bush administration and continuing with Obama, the government has been planning to replace the dollar with a new currency called the "amero" or something like that. The plan is to replace US dollars (along with Canadian dollars and Mexican pesos) with the amero overnight, so that someone who has $1 million when they go to bed one night will wake up with effectively $250,000, or 1 million ameros. This is somehow supposed to help with the national deficit, make government officials rich, and also, of course, anger every single American with any money, not to mention the Canadians and Mexicans. Obviously there will be a giant uprising with rioting, looting, etc. And that's why Obama is planning to withdraw troops from Iraq: he needs them at home to quell any uprising.
Here's what wikipedia has to say on the topic.