Meanwhile, comedian Bill Maher dug up a clip of O'Donnell appearing on his "Politically Incorrect" show in 1999 in which she says she "dabbled in witchcraft."
The context of what led to her comments is not clear, and O'Donnell is laughing while she talks.
"I dabbled into witchcraft. I never joined a coven," she said. " ... I hung around people who were doing these things. I'm not making this stuff up. I know what they told me they do," she said.
"... One of my first dates with a witch was on a satanic altar, and I didn't know it. I mean, there's little blood there and stuff like that," she said. "We went to a movie and then had a little midnight picnic on a satanic altar."
Since O'Donnell's upset of nine-term Rep. Mike Castle, opponents have unearthed unflattering age-old television clips. Her campaign didn't immediately return a telephone message Saturday, but she has in the past dismissed her previous comments.
Maher said on "Real Time with Bill Maher" that he has more clips of O'Donnell and will continue to air them until she appears on his show.
On Sunday, O'Donnell had been set to appear on "Face the Nation" on CBS and "Fox News Sunday."
Campaign spokeswoman Diana Banister cited scheduling conflicts and said O'Donnell needed to return to Delaware for commitments to church events and an afternoon picnic with Republicans in a key county where she has solid backing.
"The priorities are back in Delaware," Banister said. "Those are people who supported her, who were very helpful to her in the campaign, and she feels obligated to be there and thank them." Banister said she was unaware of the previous commitments when she booked O'Donnell for the shows. She said she canceled with Fox News late Friday and with CBS early Saturday.
"We felt really bad," she said, adding the campaign apologized profusely for canceling at the last minute. Banister said O'Donnell would be pleased to appear on any Sunday news shows in the future. On Friday, O'Donnell made her first national appearance since her primary upset in Washington at an annual Values Voters Summit. Appearances on the news shows would have furthered her national exposure.
Fox News had booked O'Donnell on Thursday. Marty Ryan, executive producer of "Fox News Sunday," said in a statement that the campaign canceled late Friday, saying she was exhausted and returning to Delaware.
"On Saturday morning, O'Donnell called us and said: 'I got triple-booked. I had been invited to go to church and then a picnic. I have to keep my priorities to Delaware voters,"' Ryan said. "The invitation to have her appear on the show remains open."
Banister said the decision was solely a scheduling issue and not because O'Donnell wasn't prepared to go on the programs.
However, the cancellations reflect a campaign of about six staffers trying to keep up after being thrust into the national spotlight. Banister said many requests are pouring in and the campaign needs a scheduler and additional aides.
Separately, "Face the Nation" host Bob Schieffer said that program received an e-mail Saturday morning canceling O'Donnell's appearance without explanation. But the campaign later called to say that O'Donnell had some campaign events.
"I can't remember when anybody has canceled on us on a Saturday, but there's always a first," he said. "If she can work it in sometime, we'll be happy to have her."