Founded by Chicago police sergeant Greg Reynolds as a showcase for collectors of antique police cars, the Chicagoland Emergency Vehicle Show has grown over eight years into a massive ballet of more than 200 vintage and in-service squad cars, fire trucks, ambulances, choppers, and emergency management units. Now under the direction of freelance television cameraman Dave Weaver, the festival starts Friday with a tour of the Aurora Regional Fire Museum and a "Lights and Sirens Parade" (which also serves as the kickoff for the North Aurora Days Festival). Day two features hourly rescue, hazmat, and law enforcement drills, in which (among other things) the Kane and Kendall County SWAT teams will pump concussion grenades into a house trailer and the North Aurora Fire Department will torch a car, hose it down, rip it up with the Jaws of Life, and extricate the "victims." Vehicles can also compete on a timed obstacle course designed by the editor of Law and Order Magazine, which Weaver says gets particularly interesting when the big boats from the 70s run. Fire buffs and little would-be Jack Bauers are frequently invited to clamber all over the gear, take fire truck rides, and join in water fights, as well as shell out for public safety equipment, parts, toys, and memorabilia. Fri & Sat 8/5-8/6, Oberweis Dairy and the Aurora Pump Company at I-88 and Randall Rd. in North Aurora, Illinois, 312-455-1212 or www.emergencyvehicleshow.com. Free.