What should I bring with me on a ride?

Map, water, something to eat (some routes do not go by any stores), things to repair a flat (pump, spare tube, patch kit, tire removal tools), ID, health insurance card, helmet, spare clothing if the weather looks nasty, sunscreen. Also useful: allen wrenches, screwdriver (or multitool), lock, money, gloves, pen and paper. You should make sure your tires are up to pressure and your bike is in good shape before the ride.