Puzzle of the . . . Month?

Here's your mission: Someone has asked you to bring them exactly two gallons of water from an outdoor pump at a cabin. The problem is that there are only two buckets in which to transport the water back to the cabin. One bucket holds thirteen gallons and the other holds seven gallons. Both are made from metal and are heavy even when empty. Your job is to have exactly two gallons of water, placed into the seven-gallon bucket, so that you can carry it back to the cabin. Can this be accomplished? If so, what is the quickest way to do it? Both buckets are empty when you start.