The US Navy's Blue Angels, are famous for all manner of aerial stunts, but one of the most popular is sneak pass. Essentially an aerial misdirection, one of the Blue Angel #6 is often in the distance, entertaining the mass of spectators. Then, out of nowhere, the F/A-18 Hornet of Blue Angel #5 flies by very low and very fast.
It's a trick the demonstration team has used for years, but at a recent show near the team's home base at NAS Pensacola, it went just a tiny bit wrong, as Angel #5 streaked directly above beachgoers. The result was just a small amount of chaos, as the powerful jet wash and wing vortices sent umbrellas, beach tents, and sand flying up into the air. It's entertaining, although there's little denying the danger a falling umbrella or tent poses to a bystander.
Check out the video, it's well worth a watch.