• Informal Bible study groups have proliferated, judging from anecdotal reports, sometimes meeting on campus, sometimes at a coffee shop or someone's home.
• Over the past 10 to 15 years, Muslim and Jewish student clubs as well as clubs espousing agnostic, humanist perspectives have appeared on public school campuses. Among the oldest, the Hindu Student Association of Bellaire High School in suburban Houston attracted 700 people of many faiths at its Holi celebration in April.
• Students in interfaith groups like Youth LEAD in Sharon, Mass., may meet off-campus, but stage workshops and programs at school.
• Students are also carving out time to pray, whether Muslims fulfilling a religious obligation or Christians delivering on prayer requests during lunchtime.
• Some schools allow released-time programs: During class hours, students leave campus for Christian, Jewish, Mormon, or Islamic instruction – some even earn academic credit.
• Schools are increasingly including Christianity, Buddhism, Sikhism, Islam, and, in some cases, the Bible in their curricula because of concern over Americans' religious illiteracy. (A 2007 study found that only 10 percent of American teens could name the five major religions.)
Many welcome the growing presence of religion.
"If the public school is to prepare people to participate in a democracy," says Mike Waggoner, editor of Religion & Education, "students are going to require an understanding of Hindus, Muslims, atheists, various forms of Christians, and so forth."
Mr. Haynes concurs, noting, "It is on public school campuses that young people learn to live with and address differences." But, he warns, if religion is going to come on campus, it has to enter "through the First Amendment door."