The Moon and Stars variety of watermelon is named for its appearance.
The medium-sized oval dark green fruits are covered with pea-sized bright yellow "stars" and usually one larger "moon." The fruits have sweet pink flesh and brown seeds. Foliage is also spotted.
Looks purple to me. Too bad the seeds are sold out! http://www.seedsavers.org/prodinfo.asp?number=266 -via J-Walk Blog
You may also get seeds at rareseeds.com or at seedsofchange.com, both companies dedicated to the promotion of the survival of heirloom varieties. Also lots of other wonderful varieties at both.