Bring yourself, your friends, your bike, your lights and anything bright and colourful you wish to wear/display while riding (flags on bamboo canes or sings on your back attached with string work best), to the area by the big West Doors by York Minster from 5.30pm. The ride will leave in the direction of its choosing at about 6pm, and last around an hour, and will no doubt end at some kind of drinking establishment.