The NBA season tips off Tuesday with four games, two of them broadcast nationally. The Celtics head to Cleveland to battle the Cavs at 7:30, followed by a Clippers-Lakers showdown at 10:30, both on TNT. The Wizards also take on the Mavericks in Dallas at 8:30 EST while the Rockets and Blazers go at it in Portland at 10:00 EST. There were a lot of shake-ups this offseason, mostly involving the power teams in the Association. The Cavs added Shaquille O'Neal, Boston brought in Rasheed Wal...