When I was in school, my class spent quite a lot of time hand whistling. It's a shame we never thought of doing anything beyond owl/train sounds.

Hand Whistler
(wish I had found a different clip)

I love stuff like this!
My grass (or cellophane) whistling is pretty limited to unlovely squawks and I can't hardly get a sound with handfarter efforts, but I sure do enjoy trying.

If you squeeze a drumstick against your cheek and blow through the top of your gumline, you can make a sound that gets the boys in band in trouble.
Girls don't make sounds like that, you know...

I'll be keeping an eye open for a hard-blowing hand drier!