Purple Moon Dance Project will celebrate its 20th anniversary, Friday April 15 to Sunday, April 17, with the presentation of “The Unforgettable Secret Rhythms of Joy.” A tale for all ages, “The Unforgettable Secret Rhythms of Joy,” introduces the goddess and a magic silver box of invisible webs. Told through the voices of children and adults, this work uncovers one’s sometimes hidden pleasures of reality. The premiere of “The Unforgettable Secret Rhythms of Joy” is part of a collaborative presentation of “Two Wings: A Shared Evening of Dance.” In the second half of the evening, Bay Area choreographer Liz Boubion will present “Maclovia’s Birds: Inspirados por el Arte de Mi Abuelita,” a piece depicting end-of-life integration, love, loss and the language of birds. “Two Wings: A Shared Evening of Dance” will be presented on Friday and Saturday at 7:30 p.m., and on Sunday, at 6 p.m., at Dance Mission Theater located at 3316 24th St. in San Francisco. Tickets are $15 in advance and $20 at the door. Children age 5 and younger are free. Purchase tickets at www.brownpapertickets.com/event/163087. Info: project@purplemoondance.org, (415) 552-1105, or www.purplemoondance.org.