Fill 'er up with vegetable oil? That's what Jim Norman and Ginger Gordon did with their 2001 Volkswagen Jetta TDI; Norman then wrote about it in the New York Times. On a 160-mile trip, the couple used only two cups of diesel fuel as a supplement to three gallons of soybean oil. (Don't try this at home unless one household member is a mechanic skilled in converting diesel engines to oil-burners, a transformation that tends to run about $2,000.)
And here's the reason the item appears in this space: After Norman and Gordon modified their Jetta, they decided it needed a new name. And so (drumroll, please), say "wilkommen" to the Volksvegan.