This is a poster design chosen from thousands for the "Art Stephen Up Challenge" contest for the show. A winner would be chosen each week, but lucky for me Mr. Colbert liked it so much it was left up for well over a month. Since the portrait was taken down it has found a new home and can be seen on permanent display at the Worcester Historical Museum (Worcester, MA) in the "Harvey Ball Exhibit." He designed the "Smiley Face".
"The Colbert Report" portrait clip (starts at 02:15)