Place the mixed blueberries, raspberries, strawberries, sliced bananas, yogurt, and sugar into a blender. Cover, and blend until fruit is chunky or smooth, as desired.
Fill paper cups 3/4 full with fruit mixture. Cover the top of each cup with a strip of aluminum foil. Poke a popsicle stick through the center of the foil on each cup.
Place the cups in the freezer for at least 5 hours. To serve, remove foil and peel off the paper cup.
