Snopes had a fun urban legend about some neat billboards. Turns out they weren't real, but were proposed as part of an art-school project. They'd be cool if they were real, though.
Don't you always wonder, though, who the first person is who tries to pass these off as true? If you read the email that came with the photos, there's someone claiming they saw these billboards on the road, which is obviously a lie, since they aren't real. Who wrote that? Why do they decide they need to lie? Why can't they just say "what a cool idea," or "what a neat project"? I don't get it.
Another cool legend, this one a true one: Check out the striped icebergs!