From San Francisco to New York, in museums, universities, classrooms and in the privacy of one’s own home, (and of course on Second Life), people are celebrating Pi. It’s the 20th anniversary of the celebration of Pi Day, an international holiday born at San Francisco’s Exploratorium.

In a story from the AP, the San Francisco Zoo was evacuated today after four tigers escaped their enclosure. Tiger attack kills one person and injures two others. One tiger was shot and the others captured.

Beginning February 15, the Asian Art Museum will present On Gold Mountain: Sculptures from the Sierra by Zhan Wang, an exhibition of site-specific sculptures by one of China's most celebrated contemporary artists.

The "floating world"— Edo Japan's urban pleasure quarters of Kabuki theaters and high-class brothels —was a place of fantasy, where drama and desire unfolded. It was out of this atmosphere that ukiyo-e (pronounced yoo-kee-oh-ey) painting emerged during the late seventeenth century and continued to flourish until the end of the Edo period (1615–1868).

Annie Leibovitz: A Photographer’s Life, 1990–2005, on view from March 1 to May 25, 2008, presents a retrospective of Leibovitz’s professional photographs as well as those she has taken of her family and close friends, and thus views a full “photographer’s life.”

Exploratorium will exhibit a live art installation by Rod Pujante on Saturday, February 16, 2008, at 11am - 4pm, at Phyllis Wattis Webcast Studio.

This Valentine's Day weekend -- on Thursday, February 14th, and Saturday, February 16th -- the Exploratorium presents special films and interactive flower-making workshops that celebrate the power of love. All events are included in the price of admission to the Exploratorium.

The Exploratorium joins Amgen at the 2008 Amgen Tour of California, an eight-day, approximately 650-mile professional bicycle stage race, to present a collection of exhibits and demonstrations designed to reveal some of the unexpected science behind bicycling and provide insight into how the body works.

Even though we live in Northern California, when we think of the approaching holidays, we think of winter, snow and ice. In keeping with that theme and with the International Polar Year, the Exploratorium presents Henry Kaiser, a Grammy-Award winning guitarist and research diver, who will accompany 45 minutes of spectacular Antarctic footage (shot mostly underwater) with narration and improvised guitar.

Don’t miss the sound of Dylan Thomas’ voice in the December 22 Exploratorium screening of A Child’s Christmas in Wales, the 1963 film that presents the story, written and narrated by Dylan Thomas, of a boy’s memories of Christmas in Wales. Sound and image also come together in amazing ways during the Holiday Animation Film Festival, from December 26-29, at noon and 2pm.

Antarctica is a vast, wild continent of snow and ice; boasting the driest desert and the coldest temperatures on the planet. Join the Exploratorium as it ventures to the bottom of the world for a series of webcasts, live events, and demonstrations.

Although the SF Bay area oil spill is no where near the size of what has happened in the Black Sea, 58,000 gallons of heavy fuel oil that is currently floating around the Bay Area is causing unconscionable damage to the sea life of the region.