A wave of Tai Chi will circle the Earth on World Tai Chi Day as, 10 a.m. local time everywhere, Tai Chi masters will lead neighborhood gatherings. Be at one session in your city as the wave passes by April 24. Speak with the session's leader and some of the participants, asking about their favorite moves.

Earth Hour will, once again, have (some) people turning out their lights for the World Wildlife Fund's climate change awareness program. This Earth Hour, be at the go-to place in your city when the lights go out. Speak with people in the dark about why they care about sustainability. Take shots of key landmarks around town that have gone dark. When the lights come back on, film them again to get the contrast.

The San Francisco Police Park Station is calling on residents with private security cameras to hand over their footage. The program is intended to expand the department's surveilance capabilities, but it's making some locals uneasy. Interview one owner of a private camera (outside a convenience store, for example) and see whether he likes the program and intends to participate. Perform streeters to get the public perspective on the newly integrated leering-eye network. See how many cameras you can spot from a couple of street corners.

Mount Diablo, named for the Devil, will be rechristened Mt. Reagan, if an East Bay man succeeds in his God mission at Contra Costa County council. Travel to the peak and show what it's like on the belly of the beast. Speak with locals in surrounding communities about the name, and whether they feel any evil presence from the site. Document anything evil. And anything nice.

Bars and liquor stores are subject to a ban on infused cocktails. Arrange for an interview with a bar owner inside his venue and get his opinion of the new ban. Speak with customers, too.

Oakland North Side street gangs will soon be illegal, if some city officials get their way. Watchdogs and the ACLU say the injunction could lead to profiling, while advocates for the proposal point to studies, which show such initiatives are impactful. Visit the supposedly mean streets of North-Side Oakland, see whether you find gangs on the street, and interview people on both sides of the debate at that location.

Cannabis Planet, a KOFY TV series, is a news broadcast specializing in the bud beat. Visit the set of Cannabis Planet, speak with the producer and anchors, and ask people on the street whether they approve of the new show.

Temple of Poi fire dancing school is fueling a fire-breathing subculture in San Francisco. Attend a class, speaking with the instructor and some students about why twirling, spinning and dancing flames are suddenly so hot.

The Bernal Heights Alemany Flea Market seems to be particularly popular lately. Attend the market, speaking with shop owners and thrifty shoppers about what the market's got that the shopping mall doesn't.

Lurking atop dozens of downtown San Francisco’s many tall buildings, out of sight of congested roadways and cramped sidewalks, are lush rooftop gardens – one of the latest fads of the green movement. Rooftop gardens are so popular, an iPhone application now offers a tour of them. Arrange to visit a rooftop garden with someone who looks after one. Ask why rooftop gardens are valuable, and how gardening up high differs from ground-level.