A couple years ago, two scruffy Walden Pond Books employees, tired of imagining how it'd look if they ran the place -- for starters, say goodbye to self-help, gardening, and business -- sucked it up and opened a store of their own. The result is the Book Zoo, a tiny but spectacularly condensed space that packs five thousand titles into 189 square feet just off Telegraph Avenue. Nick Raymond and Erik Lyngen's store has no labeled sections, but the proprietors can unearth selected items -- from List of Prime Numbers from 1 to 10,006,721 to Playboy in Braille (just the articles, sadly) -- with shocking ease. The Book Zoo also features weekly social nights, and, if you time it right, a fresh pot of coffee or tea. This may be easier said than done, however, as they're closed Monday and Tuesday, and don't open until 5:00 p.m. Wednesday through Friday. Your best bet is weekends from 2 to 10 p.m.