Sacramento’s Earth Day celebration not only gives you a great excuse to wear your old tie-dye T-shirts and Birkenstocks—and be in style doing so—it’s also an opportunity to experience both the hippy-dippy roots of the green movement and see how mainstream and even high-tech it’s become. All kinds of environmental, healthful, sustainable and otherwise green organizations and businesses will be out tabling in full force Sunday, April 11 at this year’s Sacramento Earth Day Festival, taking place from noon to 5 p.m. in Southside Park (Eighth and T streets). There’ll be kids’ activities, crafts, groovy live music on stage and food vendors representing many of Sac’s vegetarian eateries. Presented by the Environmental Council of Sacramento, the event is free. So walk, ride your bike or hop in your hybrid and make tracks to the park for some good, green fun.