My friend and former co-worker Kitsch posted this on his Facebook wall and I wanted to share, because it made me pee a little bit. Audio not safe for work due to an instance of the F-word.

What you are seeing is a wing oscillation in a Hawker 800.  Apparently it's due to the aftermarket winglets (the pointy tips) causing some kind of unexpected vibration at high altitude.

 
I don't blame the guy for swearing.  The wing oscillation would put a LOT of stress on the wing spars - wings are designed to flex rather than break, but what I see in the video can't be good for the airframe.

http://www.ainonline.com/aviation-news/ainmxreports/2013-05-15/service-bulletin-issued-hawkers-api-winglets

The article above says that a Service Bulletin has been issued for certain Hawker 800 winglets, restricting the maximum altitude the airplane is allowed to fly at to 34,000' from the previously certified 41,000' until a fix for the problem is implemented

I can only imagine how freaked out the crew was, but clearly this flight had a successful ending so that's good.