For the required Valentine’s Day candy topic, the San Francisco Chronicle visited TCHO Chocolate, a start-up headed by Timothy Childs, a former NASA scientist, and Louis Rossetto, founder of Wired Magazine. It’s the only true chocolate maker in San Francisco, crafting bars from cacao beans. With the bootstrapping practicality of a garage start-up, Childs cobbled together equipment intended for other uses, dal grinders from India, dryer duct, tape used on the space shuttle, to mix chocolate (see the result in a 2 min. video). TCHO has 30 employees and is now selling its products on the web, at its factory store, and select retailers. (A longer tour of the machines from BoingBoing TV in July 2008.)