Interesting map of Colorado's Denver area showing numbers of registered and approved medical cannabis patients. The majority of cannabis patients, to this point, use it for pain relief. On January 1, 2014, a Colorado citizen 21 or older can buy recreational cannabis.

"While medical-marijuana patients must pay the registry fee ($35) and also for a doctor's visit to get their marijuana recommendation, they won't pay the hefty sales and excise taxes Colorado voters approved this year on recreational marijuana. They are also allowed to possess more marijuana — 2 ounces or sometimes more — compared with the 1-ounce limit for Colorado recreational marijuana customers."