Mercy, mercy, mercy.

As the Sisters of Perpetual Indulgence marked its 20th anniversary on April 4, the San Francisco-based group was kicking up controversy as much as it ever has. This time religious leaders were protesting the group's Easter Sunday birthday bash on Castro Street.

This and other debates about the sisters often grow from the veil of misunderstanding surrounding them. Often accused of mocking Catholics, the sisters, who take on names such as Sister Vicious Power Hungry Bitch and Sister Missionary Position, say they simply want to "promulgate universal joy by manifesting habitually--meaning, wearing the habit," said Sister Ann R. Key. Group members, who belong to chapter houses all over the United States, Europe, Asia, and South America, raise funds for a variety of charities and vow to perpetually indulge in life and serve and protect gay, lesbian, and transgendered people.