National High Five Day falls on the third Thursday of April each year. The holiday originated at the University of Virginia in 2002, and has since spread across the nation, and around the globe.
It’s easy to get caught up in the hype surrounding National High Five Day. If you find yourself getting carried away, it is best to simply extend your outstretched hand to the next stranger who walks by, and repeat until the High Five is reciprocated. Then move on. Repeat. - copied from official site
Check out the documentary on this phenomenon HERE!