The gearheads in this town are a mixed bag: You've got your tattooed freaks, your straitlaced engineers, and lots of power-mad in-betweeners. You'll find most of 'em at the Power Tool Drag Races this weekend. With classes called "ridden" and "non-ridden" for vehicles that began their lives as chain saws, propane torches, and belt sanders (plus a new category this year for sex toys), the event has something for everyone, except scaredy-cats. Just sign the waiver and you get the "Trashy Trailer Massage and Wellness Center" and the "Synchronized Welding and Pole Dance Intermission Extravaganza," in addition to a view of weird machines racing for the coveted prize: an Edsel. This family event starts at 10 a.m. both days at Ace International Speedway, 2255 McKinnon (at Toland), S.F. Admission is $10-28; call 307-3482 or visit www.qbox.org.
-- Hiya Swanhuyser
Helicopters are the Volkswagen Beetles of aircraft. Squat and utilitarian in contrast to the sexy styling and gee-whiz capabilities of a jet, whirlybirds are seldom the object of panting fandom. But they really pull their weight in the air, where every day they ferry ailing passengers to hospitals, hoist traffic and weather people up where they belong, and transport military personnel in and out of combat. Get a new view on these flying helpmates at the chopper air show "Vertical Challenge," starting at 9 a.m. at the Hiller Aviation Museum, 601 Skyway (at Hwy. 101), S.F. Admission is free-$15; call (650) 654-0200 or visit www.hiller.org.
-- Joyce Slaton
Stern Grove's on again
For 67 years San Franciscans have been schlepping all the way down to the Parkside District for the Stern Grove Festival, and every year it's been worth it. With huge eucalyptus, fir, and redwood trees for acoustics, plus a knockout view, nice summertime weather (no, seriously), a friendly audience lounging on picnic blankets, and sweet sounds all for free, the site provides a combination so delicious that we'd better not see you wasting your sunny Sundays inside movie theaters. Instead, enjoy sets by the San Francisco Symphony (June 20), the John Hammond Trio (August 15), Senegalese vocalist Youssou N'Dour (July 18), and this weekend's jazzy opener with the Regina Carter Quintet and Tin Hat Trio. Shows start at 2 p.m. (and run through Aug. 15) at Stern Grove, 19th Avenue & Sloat, S.F. Admission is free; call 252-6252 or visit www.sterngrove.org.
-- Joyce Slaton