Oprah's back in town. But so is a political red carpet full of other super surrogates who are fanning out across the country to stump for their favored candidates, the clock ticking to Super Tuesday, Feb. 5.

And timing is everything -- candidates are pulling out all the stops this weekend to compete with Super Bowl Sunday and command attention before voters and caucus-goers in 24 states swarm the polls two days later in a contest that could amount to a Final Four: John McCain and Mitt Romney on the Republican side, Hillary Clinton and Barack Obama on the Democratic side.

Obama's campaign announced late Friday that Oprah Winfrey would return to the trail after firing up crowds before the Iowa caucuses and New Hampshire primary in December. The schedule shows Winfrey will join Caroline Kennedy and Obama's wife, Michelle, for a rally Sunday in Los Angeles. California is a key battleground for the Democrats, even though recent polls show Clinton with an advantage there.

The Illinois senator also rolled out a full schedule of surrogate appearances for Saturday. The day book has Sen. John Kerry in San Francisco, Illinois Sen. Dick Durbin in Columbus, Ohio, Virginia Gov. Tim Kaine in Savannah, Ga., and even actor Kal Penn (of "Harold and Kumar Go to White Castle" fame) in Delaware. Obama later announced the endorsement of Ethel Kennedy, widow of Robert F. Kennedy, who joined Sen. Ted Kennedy and Caroline Kennedy in supporting him. She said in a statement "Barack is so like Bobby."

Hillary Clinton the day before released an ad featuring Robert F. Kennedy, Jr. saying Clinton "is the champion of the voiceless in our society," like his father.

The Hillary-Bill Clinton unit already had split to cover as much ground as possible. Bill Clinton spent Friday in Arkansas and Georgia talking up his wife's universal health care proposals and plans to reform No Child Left Behind, and he was set to spend Saturday in Alabama and Missouri while his wife battles in California and other western states.

On Friday Bill Clinton compared his wife's vision for the country to life at a college or university -- a place where all people come together "regardless of race, gender or age" to pursue their dreams.

He also plans to watch the Super Bowl with former candidate and New Mexico Gov. Bill Richardson -- despite questions about the possibility of an endorsement, a campaign source described it as nothing more than two friends watching the game.

Among the Republicans, Romney and McCain are battling to rack up endorsements from conservatives, as they each try to dull the other's Republican stripes.

In a slap at his rival, the former governor of Massachusetts, McCain picked up the endorsement of another former Massachusetts governor, Paul Cellucci, on Saturday.

"Our nation is facing challenging times, and we need a leader who is up for the battle," Cellucci said in a statement. "John McCain is a man of great principles and proven leadership, and he has the character, integrity, and courage that we need in the White House. I am honored to support him in his campaign for president."

Sen. John Warner was set to campaign in New Jersey Saturday on McCain's behalf, as well, while McCain hits Tennessee, Alabama and Georgia.

Romney, trailing in national polls following his loss to McCain in the Florida primary Tuesday, is steadily racking up an army of conservative supporters.

Former U.S. Sen. Rick Santorum announced his support for Romney Friday. And like the Clintons, Romney has made campaigning a family affair. His son Josh Romney was set to campaign in Montana Monday, and his wife, Ann, was to head to North Dakota Saturday evening. Sons Tagg and Craig were to campaign in Maine and Georgia, respectively.

The Romney campaign has suggested the race will not be decided on Tuesday, but McCain begs to differ. He said Friday there's a good chance the dust will settle and that the sooner it's done, the sooner the party can be united.

Meanwhile, former Arkansas Gov. Mike Huckabee has toughened his rhetoric, saying Romney only recently reached "political puberty" and accusing him of flip-flopping on social issues such as abortion and gay marriage.

He hits the trail with actor Chuck Norris in Alabama Saturday, while Huckabee's wife, Janet, heads north to Alaska and Montana.

Huckabee was hoping to do well in the southern states Tuesday.

FOX News' Aaron Bruns, Serafin Gomez, Shushannah Walshe and Cristina Corbin contributed to this report.