With nine venues and counting (visit tobinarts.com for a map of participating galleries), the Tobin Hill Art Walk just got a little easier ? thanks to a free trolley. Hop on and off as you like ? but don’t miss: 1. SPACE, an exhibition exploring vacancy and architecture, as seen by artists Thomas Cummins and Enrique Gutierrez (6-10pm at Serendipity Art Space, 1908 N St. Mary’s), 2. The grand opening of caricature artist Blas Martinez’s Casa de Palmas, where artists “Soup,” Oscar Galvan Jr, and Adolph Hernandez inaugurate the gallery with live music by Erica Anthony (6-10pm at 419 E Dewey), or 3. Art for SARA at High Wire Arts: This silent auction directly and exclusively benefits the oft-overlooked Society for Animal Rescue and Adoption (a local no-kill shelter), thanks to wide-ranging contributions by artists Stephen DaLuz, Yvette Shadrock, Louis Vega Trevino, Emma Kanko, Suchil Coffman-Guerra, Henry Cardenas, and more than 20 others (6-9:30 at 326 W Josephine). Free, 6-10pm, Tobin Hill, tobinarts.com.