How to get that cool multi-layer image effect that moves in a kind of perspective when hovering or scrolling

It's called Parallax, and you can find a jQuery plugin that does this cool trick hereGithub has a nice one for their 404 page. The original DrupalCon Denver page, made by the talented Ken Woodworth is also pretty awesome, and one of those examples I want to dig into to figure out exactly what's going on.

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