For many of the 100,000-plus in attendance at Penn State's spacious Beaver Stadium that crisp November day, it was one of the most enduring images of the 2011 college football season: a pre-game gathering of uniformed players and coaches from both the Penn State and Nebraska teams in the center of the football field, kneeling and holding hands in prayer.

The storied Penn State football program was awash in a firestorm of scandalous news reports involving long-time assistant coach Jerry Sandusky and allegations of child abuse. Legendary coach Joe Paterno had been fired just a few days before the game, and it seemed that the place known as Happy Valley was reeling with an emotional mix of anguish, angst and righteous indignation.

The unusual pre-game gathering of players and coaches, then, was simultaneously a demonstration of unified support for the victims of abuse and for the entire Penn State community, as well as a public display of faith in God during a time of trauma and distress.

"We knew we were going to go into a battle against each other because it was a big game for both teams," said Nebraska's running back coach Ron Brown, who led the two teams in that mid-field prayer. "But there was something bigger … There was a humility and a sincerity and a vulnerability as all the players took their hats off and knelt before God."

Such public displays of faith (or PDFs as they are referred to in the acronymic online world) are viewed with growing appreciation by some and growing skepticism by others in a world that seems to be constantly wrestling with the proper role of faith in the contemporary public square.

Public displays of faith can take many forms: from Los Angeles Ram quarterback Kurt Warner thanking Jesus for a Super Bowl victory during a post-game interview, to Pastor Joe Nelms thanking God for his "smokin' hot wife" while offering the pre-race prayer at a NASCAR event last year; from the crosses often worn by Christina Aquilera, Rihanna and Madonna, to Justin Bieber displaying a tattoo of Jesus on his left calf; from an evangelical Christian's WWJD (What Would Jesus Do?) bracelet, to the CTR (Choose The Right) ring worn by many members of The Church of Jesus Christ of Latter-day Saints; from the tallit (prayer shawl) and kippah (skull cap) worn by many Jews, to the hijab (headscarf) traditionally worn by Muslim women.

According to Rabbi Lazer Gurkow of congregation Beth Tefilah in London, Ontario, Jews believe that the purpose of public displays of faith is not merely to draw attention, but to "affirm our faith in our own minds."

"To display your faith in public requires absolute belief and commitment," Rabbi Gurkow said. "Pushing back against intimidation and standing tall for Jewish pride (is the) antidote to the malaise that is eroding the integrity, observance and faith of American Jewry."

Rabbi Gurkow referred to the Jewish festival of Sukkot, during which "Jews walk the street with 'lulav' (palm fronds) in hand" which "we carry with pride."

"Sukkot is an outdoor holiday," the Rabbi said, "a time to affirm our belief in God and declare that we are not ashamed, that we are comfortable with our faith indoors and out."

Similarly, Christians often cite the New Testament Apostle Paul's proclamation that "I am not ashamed of the gospel of Christ" (Romans 1:16) as an explanation for their public displays of faith. In fact, New York Jets quarterback Tim Tebow — considered by many to be the PDF poster boy — had the scripture reference "Romans 1:16" inscribed in his eye black during a game against Florida International University while he was still playing at the University of Florida.

Tebow's unashamed Christianity is well-documented, and includes his own verb: Tebowing, which means to bend to one knee and assume the attitude of prayer, a PDF Tebow regularly employs during the course of a football game.

Some have been critical of Tebow's overt PDFs, citing another New Testament scripture — Matthew 6:7 — in which Jesus instructs his followers that when they pray they should "enter into thy closet, and when thou hast shut thy door, pray to thy Father which is in secret."

But others have been supportive, even congratulatory of his efforts.

"He's a class act," said Cardinal Timothy Dolan, archbishop of New York, of the new Jet quarterback. "I've followed him with great interest and I highly respect him for his unabashedly Christian values. And I've never found it put-offish or arrogant. It's just very gentle and sincere."

As far as the criticism of Tebow is concerned, Cardinal Dolan said that "because he loves Jesus, Jesus is the most important person in his life. Jesus has told us when you are with him and when you stand up with him you can expect to be insulted and harassed. So he's used to it."

Still, even some of Tebow's supporters wonder what Tebow's PDFs teach other Christians about prayer.

"The answer to our prayers is not a touchdown, or a series of passes, or a Super Bowl victory, or a new car, or a raise, or even good health," said Father James Martin, a Jesuit priest, in an article about the Tebow phenomenon in America magazine. "The answer to our prayers is much deeper than that. And much more lasting. The answer to our prayers is God."

Other athletes have found other ways to express their faith publicly. California Angel first baseman Albert Pujols points skyward with both index fingers whenever he scores a run in a baseball game. Pittsburgh Steeler defensive back Troy Polamalu crosses himself before every play, and says he sometimes prays during plays. All-star forward Kevin Durant of the NBA's Oklahoma City Thunder can often be seen reading the Bible in the locker room before games. And back in the 1960s, Muhammad Ali made one of the most powerful public displays of faith ever offered by an athlete when he gave up his heavyweight boxing title over his Muslim beliefs and opposition to the Vietnam war (he was arrested and found guilty of draft evasion in 1967).

But athletes aren't the only ones trying to live their faith more openly and more publicly these days. In Durham, N.C., the Rev. Lauren F. Winner, a teacher at Duke Divinity School and an Episcopal priest, took her Ash Wednesday "imposition of ashes" to the streets this year, praying with people and marking their foreheads with ashes while standing outside the walls of the hospital at which she works. While acknowledging that it was "a strange thing to do" and that it did not "feel entirely comfortable to me," she said she went "into public with our ashes because Jesus died in public. He didn't die in the upper room surrounded only by his disciples."

And in Los Angeles, Rimmy Kaur's PDF is allowing the hair on her head and her body to grow according to the Sikh article of faith known as kesh. This isn't easy in a Southern California culture that prizes women with sculpted eyebrows, smooth faces and waxed legs.

But Rimmy says "I want my future soul mate to fall in love with me and the guru. I am the embodiment of the divine because I keep my hair."

While not doubting the sincerity of such PDFs and their importance to their respective faith communities, Miami Herald columnist Leonard Pitts Jr. warned that public faith can be obscured if "it becomes a whirl of God talk and iconography, a cross as fashion statement, a WWJD bracelet, a football player kneeling on the field."

"That is faith externalized for public consumption, faith that runs the risk of being shiny and superficial," Pitts wrote. "It doesn't speak to the decisions we make, the people we are, when despair comes creeping into the midnight hour. Nor does it speak to any obligation toward the scabrous, the lost, the unwashed, the impoverished, the disgusted, the detested, the detestable. Indeed, those whose faith is most loudly externalized are often the ones most silent on that obligation."

Pitts concluded by suggesting that there is "duality in modern faith, a tension between faith externalized for public consumption and that which wrestles despair in the midnight hour."

"Each has its place," he said. "But only one will see you through till the morning comes."