Use a fork or toothpick to pick up one slice of banana and dip into the yogurt. Shake off excess yogurt and place onto the prepared baking sheet. Repeat with remaining bananas and the grapes leaving space between each of the yogurt-covered fruit.
Sprinkle the fruit with cinnamon and grated chocolate.
Place the baking sheet in the freezer for at least 4 hours, until fruit and frozen through.