The Cloud Project is a tricky little concept that would spray flavored condensation and liquid nitrogen into clouds, "seeding" them, and forcing flavored snow to fall from the heavens. It's pretty much straight of of a children's book.
The whole thing is purely conceptual for now; it involves certain bacteria and ice nucleation and a lot of other science-y sounding words and phrases I don't understand. What I do understand is the phrase "It will snow ice cream," and what I wish I didn't understand is "The technology is a long ways off." Don't be fooled by the existence of an actual Cloud Project van—it's purely for illustrative purposes, and only functions as a regular ice cream truck/science information center.