Place the almonds in a small container and fill with cold water to cover. Let the almonds soak overnight or for 24 hours at room temperature, until they feel soft and almost squishy when you squeeze them.
Discard the water, rinse the almonds, and place in a blender jar with 2 cups water. Pulse a few times, then blend on high for 2 minutes. Strain the mixture into a piece of cheesecloth set in a strainer over a bowl, and squeeze the cheesecloth well to extract all the liquid. Sweeten to taste if desired, and serve chilled or over ice. Store in the refrigerator for up to 3 days; shake well before drinking, as the milk has tendency to separate.