I use a waterproof case on my iPhone because I live in Seattle and I constantly drop it. Ryan Pernofski has a waterproof case on his iPhone to take gorgeous slow-motion videos of waves. I think he wins in “Best use of a waterproof case” category. For more slo-mo awesomeness follow the #slowmocean hashtag on Twitter, Instagram and Vine.
H/T to Fuck Yeah Fluid Dynamics for the video link