First off, the name is a little strange. "Pepino" is Spanish for "cucumber." Although some claim the flavor of this fruit is cucumber-like, they're not related to cucumbers. They are sometimes called pepino dulce ("sweet cucumber" in Spanish) to differentiate them from regular cucumbers. Then there's the second part of the name. While they look somewhat like small melons, kind of, and are thought to taste like some varieties, they're only very distantly related to them. Pepinos are actually part of the nightshade family, so they're closely related to tomatoes and eggplant. Confused yet? So am I.
Moving on, the pepino is native to the Andes region, in Chile, Peru, and Columbia. As such, they're commonly eaten in these countries, along with Ecuador and Bolivia. They're also grown a bit in other areas with hot enough environments, like California, Australia, New Zealand, Spain, Israel, and Kenya. They don't travel very well, so they're not as popular world wide. Their domestication is a mystery, other than their birth area. They're also not found growing in the wild.
The pepino is sometimes classified as a "super fruit," as it has significant amounts of Vitamins C, K, A, and B, as well as protein, iron, fiber, and potassium. It's also alleged to help battle liver disease and strokes, and aid in stamina and cardiovascular health. But, as usual, these affects haven't been conclusively proven. (Incidentally, I'm getting tired of writing this--for a change, I'd like to post about an exotic that has definite, scientifically proven medical benefits.)
The most common way to eat a pepino is raw, cut open, and scooped out with a spoon. Occasionally folks cook them up with honey, or sugar. Although the whole thing is edible, most people don't eat the skin, as it's tough and unpalatable. So mostly it's the pulp and seeds that are consumed.
The one I got was about fist sized--about 4 inches (about 10 cm.) long, about 3 inches (about 7.5 cm.) wide, with a tear drop shape. The outer rind was greenish/whitish/yellowish, with purple racing stripes running down it. I did the normal method, and just cut it open and had at it. The interior pulp was yellowish-orange, with a cavity for the seeds. The texture reminded me of melons. The taste was reminiscent of a honeydew melon. Only weaker--the flavor was extremely bland. I didn't detect any cucumber-like hints. Overall, it didn't taste bad, but it didn't seem worth the $3.99 I paid for it. I'm glad I got to try this somewhat rare fruit, but it wasn't very impressive.