NBA: Nuggets-Celtics headlines Sunday schedule

A special ABC double-header awaits NBA fans on Sunday with four of the elite teams in action.

The Cleveland Cavaliers have dropped two straight since the All-Star break and will have their work cut out in Orlando against the Magic. Dwight Howard has stepped up his game and Vince Carter seems to have rediscovered his shot.

But it is the Denver Nuggets-Boston Celtics clash later in the afternoon that looks to be Sunday's best offering. The Celtics are out to prove a point and may have new face Nate Robinson suited up. Road wins in LA and Portland show that the Celtics mean business and are starting their push towards the playoffs.

Ray Allen looks revived by the week off, Kevin Garnett is hungrier and more mobile and Rajon Rondo continues to provide the spark. Now Boston just need a bigger contribution from Rasheed Wallace and a healthy Marques Daniels.

Denver has gone 5-5 in its last 10 games, albeit against tough opposition, and Friday's loss to the Washington Wizards was perhaps its most embarrassing of the season. Chauncey Billups continues to light it up, scoring 28 in Washington and averaging a career high 19.7 points a game. Since January, he has been on a tear.

Carmelo Anthony is shooting it well too. He had 40 points in Cleveland on Thursday but went 0-5 in the fourth quarter against the Wizards as the Nuggets threw the game away in the final 12 minutes.

With all the hype and expectation regarding a Cavs-Lakers, LeBron-Kobe showdown in the NBA Finals this year, the Nuggets and Celtics are perhaps the two likeliest teams to prevent it. Sunday's clash will assess just h0w ready they might be to do that.