The above Report Any Joyous Activity sign appeared on a fence in Central Square (Cambridge, MA) earlier this week. If it's tied to a brand (perhaps RoseArt) it represents a great example of guerilla marketing. Really, I'm not sure where it came from, who put it there, or if any brand is involved. What I do know is it's fun and light and makes people smile. And that's why I wanted to share it with you.