In English, there are eleven basic color terms — black, blue, brown, gray, green, orange, pink, purple, red, white and yellow. These colors are fairly consistent, each with culturally canonical hues, by which similar hues are usually associated — for instance, scarlet is considered a type of red, gold is considered a type of yellow, etc.
In the Sinosphere — the regions that either speak one of the Chinese languages (such as China, Singapore, Taiwan, etc.), or have languages that incorporate massive amounts of Chinese-derived extended vocabulary and have historically made widespread use of Chinese written characters (such as Japan, Korea and Vietnam), these regions traditionally have the same word for both blue and green, indicated with the Chinese character 靑 (or its alternate glyph 青).note This character is read as reconstructed Middle Chinese tsheng, Mandarin qīng, Vietnamese thanh (poetic) or xanh (daily usage), Korean 청 cheong, indigenous Japanese あお ao, さお sao and しい shii, and Sino-Japanese せい sei and しょう shō. Most natural and traditional uses of both blue and green are represented by this word, including the color of the sea, the color of forests, etc. In more recent centuries, there has arisen a greater need to distinguish the concepts that English-speakers would understand as blue and green. The newer compound Chinese character 綠 (or its alternate 緑) came to use in Chinese, Japanese and Korean to specifically mean green as opposed to blue.note This character is as reconstructed Middle Chinese ljowk, Mandarin jī, jí, lǜ and qī, Vietnamese lục, Korean 록 rok and 녹 nok, indigenous Japanese みどり midori, and Sino-Japanese りょく ryoku and ろく roku.
However, even today, these two terms are not universally distinguished as would be understood in English. For example, forests are still 靑 (blue). Green eyes are also confusingly 靑 — they were known to traditional Chinese civilization because there were ethnic groups on the periphery of their civilization (such as the Tocharian and Turkic peoples) who often had green eyes. And even green traffic lights are 靑. But not all "natural" green things are 靑 and not all "modern" green things are 綠 — for instance, gemstones such as jade and emeralds are 綠 (green). Perhaps most confusingly, even though forests and grass are 靑 (blue), verdant flora is 綠 (green). In Cantonese, 靑 usually refers to yellow-green or lime green more often than blue.
The Sinosphere is not the only place where languages often muddle the distinction between green and blue. This has also been observed in the modern Celtic languages (Irish, Welsh, etc.), where there is not only some muddling between green and blue, but also between green and gray. South Slavic languages call blond hair blue; in this case, blue originally meant "fair", Similarly, older Italians lump orange in with red. Before about 1500, orange in English was lumped in with yellow and gold.
For further reading, see Guy Deutscher’s Through the Language Glass for an in-depth explanation of this trope and its equivalents in other countries.
Examples
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Anime and Manga
In Dragon Ball, the Super Saiyans eye color is usually greenish in the anime, but from time to time they appear blue in some Toriyama illustrations, as well as in some promotional media and certain isolated anime episodes.
The Yu-Gi-Oh! manga gave Bakura blue eyes while the first anime adaption gave him green eyes. The second adaptation (the one which made it overseas) said "screw it" and made them brown.
In The World of Ginger Fox, Ginger's eyes are sometimes blue and sometimes green. The cover art shows her with an eye color partway between green and blue.
Literature
The Odyssey and The Illiad never mention the color blue. It might be slightly odd, given all the sea-faring in the Odyssey, but this was because the ancient Greek language did not have a word at the time that meant 'blue'. Instead, the sea was called 'wine-dark'. The word that in middle-Greek came to mean blue (or blue-green, as the case may be) κυανό (where we get 'cyan') was used to describe the color of grass (i.e. what we would call green), as well as honey and the hair of blond people (i.e. what we would call yellow).
It should be noted that the color of iron, sheep and clouds were all likened to each other (gray, that is, not white) but the word used in ancient greek was the word ιοδνεφής that in later greek came to mean 'purple' or 'violet'.
This trope causes a bit of confusion when it comes to translating Chinese epics; for instance Romance of the Three Kingdoms has a handful of translation difficulties, most commonly in trying to determine if Guan Yu's iconic Blade on a Stick is the Green Dragon Saber or Blue Dragon Blade. Since Three Kingdoms uses color prominently in its descriptions, this has led to something of a lack of consistency in translations as well as in derivativeworks.
Live-Action TV
In Tokkei Winspector, the heroes are meant to reflect the traffic lights. With that said, Walter was bluish than greenish.
Similar to Winspector, Tokusou Sentai Dekaranger/Power Rangers SPD has the finishing move of the main robot use a gun with three colored barrels resembling traffic lights... with the colors being red, yellow and bluish green.
"Green" lights are tinted blue, so that red-green colorblind people can distinguish between a green light and a red light.
Oddly inverted in Samurai Sentai Shinkenger. The Shinkengers are meant to be the latest descendants of five (later six) mystical bloodlines dating back to ancient Japan. Despite this there's a separate blue and green ranger even though Japan didn't have a concept of blue being different from green when they supposedly originated.
Music
Amy Lee of Evanescence did an interview on Tokyo FM, and was complimented on her green eyes. This is where it gets complicated. It's been said that she has green eyes naturally, and wore blue contacts around the time of the first album. This interview was near the time of the second album, but in her childhood photos she had blu eyes. It gets really complicated, because in the Japanese translation, the DJ used the English loanword グリーン, or green.
Miku Hatsune's thematic color tends to fluctuate between any given shade of green or blue, depending on the artist.
Somewhat justified in that wood is associated with air in Wu Xing (contrary to the Japanese "translations" listing Seiryuu as earth and Byakko as air), so you can either go along with Wind is Green or simply see the Azure Dragon as a manifestation of the sky.
Brown in a much more common a color for lentil stew than red. It's quite likely that when the Book of Genesis was composed, the two weren't distinguished in Hebrew.
Video Games
In the early days of Super Mario Bros, the color of Luigi's clothes was inconsistently portrayed as blue or green. It took a little while before the vivid green color became firmly established.
Fox McCloud from Star Fox is one of the better documented examples of this trope. In the 1993 comic, his eyes were green in the early pages, then blue through the rest of the comic. They remained blue in Star Fox 2. Star Fox 64 had a particular Art Shift that did not show eye color at all, but Farewell, Beloved Falco and Star Fox Adventures firmly established him with emerald green eyes. But this began to slip again in Star Fox Assault, where most of the official art showed him with green eyes, but at least one picture not only showed him with blue eyes, but the blue faded to green within the same irises. They're green again in Super Smash Bros. Brawl.
In Metal Gear Solid 3, Big Boss' eyes are described as blue in dialogue, but they appear green. Snake's eyes were also dark green in Metal Gear Solid 2, but described in his bio in Metal Gear Solid 4 as blue and appear clearly blue in that game.
Several Pokémon are listed as "green" in the Pokédex, when most Westerners would consider them teal: specifically, Bronzor, Bronzong, Golett and Golurk are all listed as "green"; this is especially unusual for the last two as they were designed by an American, James Turner (though the illustrator, Ken Sugimori, is Japanese).
There are several orange Pokémon as well. But the Pokédex ends up listing them as either red or brown.
Visual Novels
Torahiko Ōshima from Morenatsu is usually drawn with blue eyes, but some of the artwork shows him with green eyes.
Real Life
The point at which more finely differentiated color terms entering a language seems to correspond to the development of that culture's ability to produce pigments of those colors. Many hunter-gatherer cultures have rather limited color vocabulary (e.g. three colors: 'dark' (blacks), 'warm' (reds), and 'cold' (whites), corresponding to the earth-tone pigments available to them. Most bronze age languages (Mycaneian Greek, Chou dynasty Chinese) did not have words distinguising blue from green corresponding to a lack of technology to create pigments or dyes that were distinguishably either blue or green (an expection was Ancient Egyption that, uniquely, had a word for blue and a blue pigment made from calcium copper silicate), by the Iron Age most languages had up to 6 distinct color terms including seperate terms for blue and green.
In Japan, "go" traffic lights are green, but art of traffic lights is blue. This shows up in an early episode of Transformers Cybertron, where we see an actual traffic light (well, it's a robot in disguise, but still), and a slideshow presentation of a traffic light, and they're different colors.
Related: The three forms of Kamen Rider Accel are supposed to be based off of the three colors in a traffic light. These forms are colored red, yellow and, you guessed it, blue.
— black, blue, brown, gray, green, orange, pink, purple, red, white and yellow. These colors are fairly consistent, each with culturally canonical hues, by which similar hues are usually associated — for instance, scarlet is considered a type of red, gold is considered a type of yellow, etc.
In the Sinosphere