Via CNET, I managed to run across a story about a London-to-Ulaanbator rally that requires that all cars be powered (or underpowered, as the case may be) by a 1.0 liter engine or less.
To put that in perspective, the only new car sold in the US today that would be able to meet that requirement is the Honda Insight, and I doubt that it would really qualify, since it’s a hybrid.
There are several suggested routes; the northern passage goes through Sweden, Finland, and Siberia (it’s the route I’d choose—more daylight hours), while more southern options include scenic travel-spots like Iran, Moldova, Ukraine, Tajikistan, Kyrgyzstan, and many others. In theory, it’s possible to traverse northwestern China on the way to Mongolia; in practice, it’s somewhat less than advisable.
Still, I have to admit that trying to coax an underpowered Renault or original Mini Cooper through the Khyber Pass sounds like a lot of fun. And as a race, it’s a hell of a lot more interesting than the Daytona 500.