Second Life is a 3-D virtual world. In fact it is very much like a WikiWithProgrammableContent except the content is primarily in ThreeDeeGraphics as well as multimedia and text.

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And if that isn't fancy enough for you, try "Third Life" (a KitKat commercial)

http://www.youtube.com/watch?v=ymwEycc1m1A

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See also VrmlToSecondLifeTranslator