Commonly recognized as Blue Tea, Butterfly Pea is the dried flower and petals of the Clitoria ternatea plant. Caffeine-free, it can be used to make a naturally blue herbal infusion.  The brewed blue liqior can change color to purple or pink when lemon, lime or other ingredients that change the pH are added.
 
Experiment by creating ice cubes to add to other beverages, blending it with other herbs or fruits, or infusing natural color into baked goods.