Legalisation, regulation and taxation: not a matter of if, but when. Find out if your ancestors existed in areas when it was legal: http://www.livescience.com/48337-marijuana-history-how-cannabis-travelled-world.html
Keep up to date with science by downloading an RSS reader (e.g., Mozilla Thunderbird) and adding the following feed:
Repeat for topics you're interested in, e.g.:
I like to monitor an expert and a prohibitionist:
The first time you add a feed you'll have ~100 articles each feed to skim, but generally only ~10 new articles (usually duplicates and depending on keywords) appear daily. I keep &num=100 &max=100 because often I'm away from the net for long periods and miss things, but you can experiment reducing these numbers to say, 20.