Any kind of fruit you want, I used blueberries and peaches.
I mashed the peaches, but you can leave it in chunks.
Mix water, lemon juice, and honey. Use as much or as little honey as you like. You could also use some plain yogurt with honey instead of the water.
I put my fruit in and then filled the rest with the water. I used a lot of fruit, but if you want to use less you have to let the popsicle get slushy first, and then mix in your fruit. That way it will not all sink to the bottom of the mold.
Some other combinations that looked yummy were watermelon puree and fresh mint, strawberry banana, and lemon and ginger (I love ginger and think it goes with pretty much any fresh fruit).