This is pretty neat!
Link: The New SMS: Smoke Messaging System on PSFK
New technology from architecture and design studio Minimaforms combines cutting edge communication with its most primitive form. It allows you to project SMS messages onto smoke plumes, forming text signals in the sky. The system was installed in two locations at the OFFLOAD festival in Bristol, England last month
You can see a picture of this at the above link — talk to Minimaforms for more details.