The 18th annual Equality Forum, Philadelphia's GLBT super event, whichkicked off yesterday, is expected to draw more than 50,000 participants over the next five days in support of the international gay-rights movement.

The Equality Forum, which started in 1993 as PrideFest Philadelphia, has expanded from a weekend event with 15 participating organizations to a weeklong GLBT (gay, lesbian, bisexual, and transgender) summit featuring more than 50 panels, parties and performances. "It's the global GLBT summit," said executive director Malcolm Lazin. "There's really no larger event."

Lazin said Philadelphia's history of activism makes the city a prime location for such a gathering. "I think it's a logical site because it's where the original gay and lesbian movements began," Lazin said, referring to the early protests for gay rights in the mid-1960s at Independence Hall.

These original activists chose Philadelphia in part because it is home to the Liberty Bell, which was a popular symbol for civil rights in the 1960s.

"We are the civil-rights movement du jour, as much as the civil-rights movement of the '60s and into the '70s was certainly the African-American movement," Lazin said.

"Civil-rights movements go nowhere unless they enlist the support of the mainstream," he added, noting that the goal of Equality Forum 2010 is to do just that.

A highlight will be Sunday's National Same-Sex Commitment Ceremony, staged to increase awareness of the 1,138 federal marital benefits denied to same-sex couples.

Other high-profile events include the big-ticket ($200) International Equality Dinner on Saturday, which honors lawyers David Boies and Ted Olson, who opposed each other in the 2000 Bush v. Gore election challenge before the Supreme Court but who now are working together to challenge the ban on gay marriage.

"They are straight allies," Lazin said, "and if they are successful, this is essentially Brown v. Board of Education," the case that outlawed racial segregation in public schools.

Among other summit highlights are:

* Tomorrow's sports panel includes, among others, Brian Sims, who played for Bloomsburh University and was the first openly gay NCAA football captain; former Inquirer reporter Gail Shister, who was the first out female sportswriter; and Dee Mosbacher, producer/director of "Training Rules," about Penn State's women's basketball program. (Arts Bank, 601 S. Broad St., 8:30-9:45 p.m. tomorrow, free.)

* SundayOUT! - the region's largest GLBT street festival - moves from Old City to the Piazza in Northern Liberties this year. Vendors will line the streets outside the Piazza. In the Piazza itself will be live and Jumbotron entertainment from noon to 7 p.m., including a fashion show, Philadelphia's Gay Men's Chorus Cabaret, dance performances and the Philadelphia Freedom Band.

For more information and a complete list of activities, visit www.equalityforum.com.