If this annual canyon hootenanny keeps growing, some developer type will no doubt demand an environmental-impact report. No kidding, it's a classic grassroots David vs. corporate Goliath struggle out in the Santa Ana Mountains, with local activists, including the Sierra Club, fighting to preserve the area's last wild lands against the proposed construction of 4,000 homes. This year, organizers raising funds for the righteous work of the Canyon Lands Conservation Fund (CLCF) expand their reliable lineup of outdoor, under-the-stars music and eats, making the event your one-stop post-Earth Day anti-development, pro-tree shindig. Besides dinner and activist speakers, live music and a costume contest (Butterfly Girl, you broke my heart last year. Find me. Frog Boy), there'll be a Plein Air art exhibit and juried show (and sale, naturally) and an environmental expo with eco-friendly stuff you won't find at Wal-Mart—not that you'd shop there, anyway. And the art is quality stuff, not your uncle's paint-by-number ship in a storm, curated by the Southern California Plein Air Painter's Association, with a big chunk of sales going to CLCF. Performers include local bluegrass and blues pickers and thumpers, the all-woman acoustic outfit Lilies of the West, and a Grateful Dead cover band, all on the grounds of Baker Ranch, a forested glade hidden in the hills of Blackstar Canyon. Find a map. Carpool with eco-friends. Bring your checkbook.
Third Annual Tree Huggers' Ball and Go Green Expo at Baker Ranch, Blackstar Canyon, 27912 Baker Canyon Rd., Silverado, (714) 649-2820; www.canyonland.org. Sat., 4 p.m. $35; $60 per couple; kids 6-12, $15; children 5 and under, free.