Put 2 cups of blueberries in a large mason jar with a fifth of vodka. I poked each one with a knife. Because I had them, half of the berries were frozen, which explains why the vodka is turning a vibrant shade of purple. Let sit for two weeks. Drain through sieve or china cap, press lightly.
I have also done this with a fifth of vodka and a couple of inches of fresh ginger, peeled with a spoon and coarsely chopped. It was unbelievably good, especially since the vodka was really bad before.