Chelsea Books is a mostly used bookstore for the ironic history buff in the family. At this cozy, homey shop in the Inner Sunset, you can find that folio-size tome on hippie communes you didn't know you needed. It's also the place to get your hands on biographies of now-campy figures from the past. Just think of the gag-gift potential in a biography of Evel Knievel, or -- for your gay friends -- the autobiography of Anita Bryant! The sex section is especially riveting. A recent purchase, Together Sex, copyright 1973, details "how to throw an orgy party," right down to a supply checklist: wet-naps in every room. The fiction, poetry, and art sections are all good at Chelsea. But with so many hilarious, dated-seeming publishing projects to laugh over, who wants to seriously look for something "good"?