I read this awesome article a while back about futuristic roadways equipped with LED lights built in.
http://www.physorg.com/news171545860.html
While it would be very disruptive to themeing especially on Main Street USA. I have always thought it would be amazing if this sort of technology was used at night for both crowd control and entertainment purposes.
Think about the fiber optics in the ground at Epcot but on a much larger level. Think of how it could be beneficial in showing where people can or can't stand for parades and fireworks as well.
In either case, its an idea that will never happen.