VW XL1 was a concept car by Volkswagen unveiled at the 2013 Geneva Motor Show earlier in 2013. This car has a nominal fuel efficiency of 0.9 l/100km (313 mpg Imperial)! which means that its the most fuel efficient car in the world.  The XL1 weighs just 800 kg (1764 lbs). 

The bad news is that for the time being only 250 cars will be produced at the price of 111000 Euros ($143000) and they will be delivered by spring 2014. Its not yet clear if this concept car will ever be mass-produced. 

The good news is that VW plans to create a sporty variant of the XL1, the XL Sport, powered by the V2 1200 c.c., 190 PS Ducati Panigale engine! Thus forget the fuel economy, vive le sport as a French car manufacturer would say! It should be reminded that Ducati was bought by the VW Group in 2012.