On Saturday, Sinners and Saints Tattoo  will host its second annual “Fender Bender’’ celebration in Onset. The event will take place from 11 a.m. to 4 p.m., rain or shine, and will feature muscle cars, hot rods, and professional wrestling stars Jimmy Hart,  Tito Santana,  and Nunzio.  Attendees can enter a raffle to win Boston Red Sox and New England Patriots memorabilia, Zildjian  cymbals, a set of drumsticks autographed by Aerosmith drummer Joey Kramer,  and other prizes. “We got almost 3,000 people there last year,’’ said Roger Chouinard,  a Wareham native who is organizing the event. Chouinard is hoping for an even bigger crowd for this year’s event because the proceeds will benefit John Dykeman,  a 10-year-old Sandwich boy who has muscular dystrophy.