from that OCR article:
"The first clue is: This market caters to "greenies." At 11 a.m. Saturday, look for @FoodNetwork to Tweet the final location for the free lunch."
Seabirds schedules semi-regular stops on Saturdays at the OC Green Market in the parking lot of Irvine Valley College. They are also scheduled there on the following Saturdays, Sept 10, 17, 24. So if you want to get a jump on everyone, that is probably the clue to which the article is referring.