Brandon Generator is a web-animation which is created by Edgar Wright and Tommy Lee Edwards, and the plot is changed by how users interact with the story. For example:
Brandon is a writer with writers block and wakes up from a caffeine black-out to find that someones been giving him ideas. The next episode shows the ideas (which the users create) and how they've changed Brandon's world.
Do keep in mind that it's heavily endorsed by Microsoft, but more subtly during the later episodes. By the way, anyone contributed?
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