Credit: marinationmobile.comMarination Mobile’s Famous SlidersMobile Chowdown 3 is a showdown between Seattle food trucks and their more established mobile competitors from Portland. Making the trip north to ply Seattleites with food are Burgerville, Koi Fusion, Potato Champion, and Whiffies, which serves both savory pot pies and sweet pies. Representing Seattle are Marination Mobile, El Camion, Kaosamai Thai, Gert’s BBQ, Skillet Street Food, Hallava Falafel, and Veraci Pizza. 10 a.m.-3 p.m. Sat., March 13. Free entry. Occidental Avenue South between Edgar Martinez Drive and South Massachusetts Street. Free parking at Safeco Field Garage.