The NBA's championship-winning game for the Dallas Mavericks on Sunday was seen by nearly 24 million people, leading ABC to its most-watched week during the slow summer season in nearly 10 years. The Nielsen Co. said the Mavericks' series victory over the Miami Heat was seen by an average of 17.3 million people over the six games. That's a little less than the viewership for last year's Lakers-Celtics series, which had the advantage of going to a climactic seventh game.