Damn I wish I had a night picture...The signiture 25-story Wells Fargo Tower in El Paso, Texas, actually has a multi-colored light grid on the exterior of the building to spell out whatever it wants in whatever color. Usually during college football season they have "UTEP" on the grid in orage and blue. When Norwest Banks owned the buildingt there was a giant green "N" on the building at night.
Courtesy encyclopedia.quickseek.com