A week or two ago there was a free Wiz Khalifa concert in Government Center. Anyone familiar with the music of Wiz knows that he will probably attract a lot of weed-smokers.
I didn't think it was a great concert - poor acoustics, couldn't really see anything, and I'm not a huge fan of Wiz to begin with - but I still thought it was a cool experience. Easily the biggest group of people I've ever been a part of where EVERYONE was smoking.
And the coolest thing of all? Mayor Menino (who hosted the concert) was bouncing around on the stage, with Wiz, the entire time. There's no way he didn't even get at least somewhat of a contact-high.