(AP) - Barack Obama aims to weave the personal with the political Thursday night as he tells 75,000 supporters in a football stadium - and millions more at home - how as president he would make a difference in their lives.
He put finishing touches on his speech Thursday morning, but also found time to shoot some hoops on a basketball court at the Denver Athletic Club.
He also spoke to a luncheon for female Illinois delegates. "I had this speech tonight. I wanted to practice it out on you guys. See if it worked on a friendly audience," Obama joked. He didn't actually give the speech.
"I haven't forgotten where I came from," he added. "It's because of all of you that Michelle and I have this great honor of helping to lead the party and win back this White House."
Aides said his address accepting the Democratic presidential nomination would be a "direct conversation" with Americans on what's at stake and the risks of putting another Republican in the White House.
Obama, who first gained national prominence just four years ago in a speech to the 2004 Democratic Convention as a little-known Illinois state senator, was also expected to draw contrasts with rival John McCain and try to dispel any remaining concerns Americans might have about his capability to govern.
Republican McCain said in an interview that aired Thursday - but was taped on Wednesday - that he wasn't ready to announce a running mate just yet, although he was expected to do so by week's end, possibly Friday.
Obama accepts the Democratic nomination Thursday night at Denver's Invesco Field at Mile High.
Three hours before the day's program began, as many as 1,000 people were lined up at a pedestrian entrance to the stadium. On a hot, sunny day, security people were advising the crowd to drink a lot of water. Nearby street parking was going for as much as $80 a space.
"Senator Obama's speech tonight will be as he himself has characterized it, more workmanlike, a very direct conversation with the American people about the choice we face in this election. About the risk of staying on the same path we're on, the risk of just more of the same versus the change we need," Obama spokeswoman Anita Dunn said in a conference call with reporters.
McCain appeared poised to name his running mate soon after the end of the Democratic convention, in hopes of curbing any bump in the polls that Obama might get as he and running mate Joe Biden and their wives begin a three-day bus tour of battleground states on Friday, beginning in Pennsylvania.
McCain, too, planned a rally in Pennsylvania, on Saturday.
He said in a radio interview that he was bringing to that event both former Pennsylvania Gov. Tom Ridge and former Massachusetts Gov. Mitt Romney, two of the leading names on his short list for vice president. But he cautioned against assuming that meant either one would be the pick.
"I haven't decided yet, so I can't tell you," he told KDKA NewsRadio in Pittsburgh in an interview that was taped on Wednesday.
Another Republican mentioned often in vice presidential speculation, Minnesota Gov. Tim Pawlenty, was in Denver as part of a GOP team criticizing Democrats. This afternoon he abruptly canceled several media interviews, without explanation.
McCain, in his Pittsburgh radio interview, praised Ridge, a longtime friend and frequent campaigning partner.
"He's a great American and a great and dear friend and I rely on him and I have for many years," McCain said.
A Ridge candidacy could irk some conservative Republicans because of his stance in favor of abortion rights.
Both campaigns see Pennsylvania as an important battleground.
"This is not hyperbole: We cannot win without Pennsylvania," Biden, who spent part of his youth in Scranton, Pa., told Pennsylvania delegates at a breakfast Thursday.
Obama hopes Biden's blue-collar appeal will let him avoid a repeat of his Pennsylvania primary loss in the Democratic primary to Hillary Rodham Clinton.
Obama stood ready to accept the Democrats' nomination, the first black person to claim such a prize, on the 45th anniversary of Martin Luther King Jr.'s historic "I Have a Dream" speech.
The Democrats officially made Obama their presidential choice and Biden their vice presidential nominee on Wednesday.
The McCain campaign said it planned to air a new ad that will run in battleground states Thursday night around the time of Obama's address. In it, McCain will look into the camera and speak as if he were talking directly to Obama, said McCain spokeswoman Jill Hazelbaker.
Obama played basketball Thursday morning at the Denver Athletic Club. He waved to supporters as he came out, wearing a Secret Service cap, a brown shirt and athletic pants.
He was also doing some final work on his speech, said campaign spokesman Dan Pfeiffer.
"Doing the speech at Mile High is an important point for our campaign. It's symbolic of how Sen. Obama won the nomination. It will show how Obama wants to involve people who are not usually involved in the political process," Pfeiffer told reporters.
Republicans, keeping up a theme they first used when Obama drew tens of thousands for an appearance in Berlin, derided the acceptance speech's stage as befitting a celebrity with little actual accomplishment.
"This Roman-like facade, a facade with Roman columns, is a perfect metaphor or icon for the point that it's an interesting production, but behind it there's not much there," Minnesota Republican Gov. Tim Pawlenty told ABC.
Democrats have responded by noting that President Bush's acceptance speech in 2004 also took place on an elaborate stage that included similar columns.
The drama of Obama's long, emotional primary struggle against Clinton behind him at last, the Illinois senator's convention speech will propel him into a tough sprint to Election Day.
A modern-day technological effort was under way to get most of those packed into the stadium to form the world's largest phone bank - text-messaging thousands more to boost voter registration for the fall.
Obama accepts his party's nod on a day few might have imagined decades ago, when King fought for civil rights.
"This is a monumental moment in our nation's history," Martin Luther King III, the civil rights leader's eldest son, told The Associated Press on Wednesday. "And it becomes obviously an even greater moment in November if he's elected."
Obama was just 2 years old when King addressed a sea of people on the National Mall in Washington on Aug. 28, 1963.
Adding a touch of celebrity to the convention's final night, singers Sheryl Crow, Stevie Wonder and will.i.am were scheduled to perform, with Academy Award-winner Jennifer Hudson singing the national anthem.
(Copyright 2008 by The Associated Press. All Rights Reserved.)