Blend the blueberries in a food processor or blender on high speed until nearly liquified into a smoothie-like consistency. See above for a photo. Pour the thick blueberry liquid into a large bowl. Stir in the agave/honey. Add the yogurt and very gently mix everything together. If you want a tie-dye, swirly look to your popsicles-- do not fully blend the yogurt and blueberries. You want those patches of white and blue. The mixture will be thick. Taste it. If you want it sweeter, you can add a little more agave/honey. Pour mixture evenly into each popsicle mold. If your popsicle mold has slots for sticks, you can insert them before freezing - if not, freeze for 2 hours, then put a wooden popsicle stick in the middle (that is what I did). Continue to freeze for an additional 4-6 hours or overnight. Run popsicle molds under warm water to easily remove. Eat on a hot day. Enjoy!