A good beginner's smoothie, especially in winter when citrus is abundant - and not too many other fresh fruits.
Juice of two grapefruits
1/2-3/4 cup pineapple chunks (frozen is fine)
1/2 cup cherries (frozen is fine)
1 cup spinach leaves
1 teaspoon ground flax seeds
Drizzle of agave syrup, if desired
Blend and enjoy.