Q: How much has the price of gasoline increased recently?
A: Since the beginning of the year, the average price of gasoline has increased by 42 cents, from $3.36 to $3.78 per gallon. That's from the US Energy Information Administration, and it's an average of all grades, all formulations, across all regions of the country. The price has gone up more in some regions (like California) and less in others (like the Rocky Mountain states). You can see the regional variations here.
Q: How come it's gone up so much?
A: Gasoline prices are linked very tightly to crude oil prices. Stuart Staniford has the wonky graph here and the wonky explanation: "Technically, 97% of the variance of the price of gas is explained by the price of oil."