You dont always need a spin instructor to take a spin class. Take yourself. Spin through rough patches of dirt, up a mountain, in tall grass, on the beach by the ocean. Change up the resistance as you change landscape in your mind's eye. Keep yourself motivated with a little Confessions on a Dance Floor or Chocolate Starfish and the Hot Dog Flavored Water. Aint no joke.
For anyone interested in self spinning keep in mind that an instructor will at least remind you of proper form, hand positions, breathing techniques, etc. It is fine to train alone but first learn the proper techniques in order to avoid injury. On the other hand you can just get on a real bike and take yourself to great places while getting a workout.