My entry for the Tap'dNY Keep the Bottle Contest involves making a bong out of a used water bottle, a stem and cone, and a lighter. What's better than saving the environment and getting high while doing it.
Note: Use this at your own risk. Smoking is bad for your health, and if you get caught it's also bad for your criminal record.
Before anyone start flaming I would like to direct them to http://www.washingtonpost.com/wp-dyn/content/article/2006/05/25/AR2006052501729_pf.html