On the first day of Free Fuel Week the Zynga gods gave to me . . . 1 free fuel refill.
On the second day of Free Fuel Week the Zynga gods gave to me . . . 2 free fuel refills
... and you can guess the rest!
If you visit FarmVille consecutively each day of the Free Fuel Week, the number of free refills given should increase per day.
This article originally posted at FarmVille Freak.