Etsy seller Will Rockwell made this "audio amplifier" from a trumpet. There's no electronics or circuitry - the acoustics of the victrola amplifies the iPhone's music on its own.
This is actually one phone photoshopped and video-edited to look like several phones, but the effect is still pretty cool.
(at least one of you won't bother to read this and will call it out for being shopped in the comments anyway).
Also it's Mark Foster's birthday today (leap year baby!) so there's that.