So this means the gas station will be paying me to fill up my tank, right?

Short version: Speculators that ruin the market by buying contracts they'll never use but resell to others got fucked because no one is buying.

Their actions are gambling and it has been illegal to do this since the 1930s Great Depression. A certain brainless idiot named Bush Jr. helped repel the part of the law that made this practice illegal (he wanted cheap oil to disappear, anyone else remember gasoline being $0.99 per gallon in California before him?).