Have you heard about The Uniform Project? The idea is that one girl wears one dress for one year as an exercise in sustainable fashion. Every day she has creative license to "reinvent" the dress with layers, accessories and all kinds of accouterments, the majority of which are vintage, hand-made, or hand-me-down goodies, as an experiment in exactly what you can do with just a basic black dress. She gets more creative on some days than others, but there are lots of easy ideas you can steal to dress up something of your own!
You still need your share of accessories, but I do like the idea of better purposing some of the clothing we already own, and combining it in different and creative ways.
This actually reminds me a lot of a similar project from 2005 called the Brown Dress Project, where a woman named Alex Martin wore the exact same dress every day for a year in an effort to give a little f-you to our economic system that pushes over-consumption. Hers was less of a fashion statement than an attempt to confront consumerism, but should still get a nod for the effort. Same dress, every day for a year? Probably smart that she chose the color brown.