This is a really cool video taken on an iphone from the inside of a guitar! The frame rate and rolling shutter give a really cool slo-mo vibration effect.
"I just happened upon this trick when testing what it was like filming from inside my guitar. *Note this effect is due to the rolling shutter, which is non-representative of how strings actually vibrate."
The description of the youtube video also has some tips if you want to try this yourself!