For those interested in finding new ways to express themselves, without causing any physical damage to property, then light writing may be what you're looking for. Utilized for the first time almost 100 years ago by Pablo Picasso, awareness for the new style of graffiti spiked with mainstream advertisements by Sprint back in 2007.
This particular design is called Halo, and created by Aïssa Logerot based out of Paris. He has several other "light-style" creations, but the Halo is particularly interesting. While there are other formats for graffiti artists to utilize, the Halo replaces the standard nozzle on a spray can with a tiny LED, which can then be turned on at will.
The real ingenuity comes in Halo's manipulation. Not only can the LED's brightness be altered, but the colors are interchangeable. And to make it better, the intensity of the light, as well as the strength of the battery, can be recharged by simply shaking the can, just like a real spray can. There isn't any word on a release date as of yet.