A 9-mile horseback trip up the Rillito River starts at Green Fields Country Day School (6000 S. Camino De La Tierra) at 2 p.m., Saturday, April 24, and ends with a gala dinner, silent auction and barbecue at Hacienda del Sol. The deadline to reserve a horse for the trail ride was Friday, April 9. $150 for the ride; $200 for the ride and gala dinner. The event is a fundraiser for Green Fields Country Day School. Tickets for the gala alone are $75 in advance; and $100 at the door. Student prices are $100 for the ride and a barbecue; or $25 for the barbecue only. Call 297-2288, or visit www.greenfields.org for more information.