DesignSponge showed how to turn a recycled wine bottle into a very cool tiki torch (via Garden Therapy).
wine bottle tiki torch - would be perfect if it was possible to put citronella candles in it... do they make those that skinny??
Self-watering planter made from recycled bottles. (I'd want to try this with a 2-liter plastic bottle, and cut the top off, so I could get the root system out intact for transplants.)