Combine 2 cups yogurt, scrubbed oranges, sliced frozen banana, 1¼ cups frozen pineapple and 1½ teaspoons ginger in a high-speed blender; process until smooth, 1 to 2 minutes.
Alternatively, process all ingredients in a regular blender until smooth, 2 to 3 minutes, stopping to mash down the oranges and scrape down the sides as needed.
Divide the mixture between 2 (20-ounce) glasses and garnish with orange slices.
