What you see here are some of the strangest addictions I've ever heard of in my life:

[link]http://www.oddee.com/item_96496.aspx[/link]

Addiction to chalk-eating:

http://health.discovery.com/videos/my-strange-addiction-clips-chalk.html

Tanning addiction:

http://health.discovery.com/videos/my-strange-addiction-clips-tanning.html

List any strange addictions you've come across....those listed above were the strangest I've come across so far...