I just watched
Pucker Up: The Fine Art of Whistling (2005) and I recommend watching it only if you like whistling and like documentaries.
If for some reason, you hate whistling and whistlers, watch something else.
Basically, it follows different whistlers from different backgrounds on their quest to become the
best international whistler. Along the way, the documentary addresses whistling in history
and popular culture as well as various techniques you may never have heard of. There are
even a few cultural groups discussed that use whistling for communication.
It's a really compelling documentary, and I found myself whistling around the house afterwards.
If anything, the whistling talent alone makes this film worth watching.