Make like Antiques Roadshow, and delight your inner decorator at this year’s SF Modernism show and sale. Whether you’re obsessed with art deco or gaga for midcentury modern, the 20th-century design exhibition is a treasure trove of collectibles. Look out for gems by architect Frank Lloyd Wright, pottery by artist Van Briggle, a Stickley craftsman leather chair, and funky Bakelite bracelets. If you’re not in the market to buy, check out the display of textile designs by Oakland-based Dianne Ayres or the fashion show featuring Gatsby-era vintage clothes and accessories. Aug. 13–14; Concourse Exhibition Center, 635 Eighth St. (at Brannan),