This is crazy! Recently a group called Studio Vollaerszwart installed 50,000 fluorescent pink dots on a street in Rotterdam, The Netherlands as part of a big art festival. Can you imagine how cool that would have been to see? It's like something out of a children's book!
The studio has done some other amazing projects too; check out this, this, (holy cow!) this, and (wow!) this.
(thanks to Design Mom for the tip)