As the Northwest sidles lazily into autumn, there are still a few market events in store. The Columbia City farmers market is spotlighting the AARP set on Wednesday, Sept. 8: Nutritionist Marta Vaughan will demonstrate how to concoct delicious, easy-to-prepare dishes for seniors using local fruits and vegetables. For those unwilling to cook their own veggies, Billy Allstot of Billy's Farm in Tonasket will be roasting sweet and hot peppers at the University District and West Seattle markets. On Saturday at 10 a.m., the U-District market holds its annual tomato tasting; shoppers are encouraged to sample as many varieties as possible, then vote for their favorites. The results help farmers plan what to plant next year.