The Double Harmonic Scale is a fun scale that has a sort of exotic sound to it. This is also known as the Gypsy Major Scale or the Byzantine scale. The scale is built with the minor third in two places (between b2 and 3, and between b6 and Major 7): Root, b2, 3, 4, 5, b6, Major 7. Here is a great visual and more details on it, as well as examples of some wonderful classical compositions where you can hear it used.