I’m a big fan of Improv Everywhere. Essentially they describe themselves as a ‘long form improvisation troupe which executes pre-planned ‘missions’ which usually involve socially awkward or unusual situations. They’ve been a rich area of inspiration for ad agencies (just check out the T-mobile rip off of their station flashmob!), and always provide entertainment. Check out their ‘no pants subway journey’ and their latest ‘pop-up wedding’!