Protesting the Washington Redskins' nickname on the grounds that it's supposedly racist, an American Indian tribe has purchased a 60-second ad to air during halftime of Game 3 of the NBA Finals.The ad was slotted for the Chicago, Dallas, Los Angeles, New York, Sacramento, San Francisco and Washington markets Tuesday night. It aired in Miami during Game 2 of the series.The Yocha Dehe Wintun Nation of northern California purchased the time for the airing of a 60-second version of the National Congress of American Indians' "Proud To Be" ad. A longer version is available online."Native Americans call themselves many things," a man's voice says on the commercial. "The one thing they don't ... "