Once took a trip to Alaska to visit a friend. He was so excited to show me real mountain snowboarding, and boy did he have a surprise for me.
One night had a real good dump of snow, and he took me off trail. We'd been keeping it pretty mellow, with me being the more experienced rider, though only had done the midwest.
We rode into this mellow canyon, must have been a river bed or something, like a natural half pipe. Just got into a rhythm carving back and forth, following him, pushing higher and higher slashes on the walls.
Then, on one frontside wall, maybe 20 foot high, I look over my shoulder, and the world fell away. The whole thing dropped down into a steep wall that had to be 100 foot high. Powder up to my waist, almost in free fall, we ran down like bats out of hell.
When we hit the bottom I flopped down, completely covered in snow, and couldn't stop laughing and grinning for a good 5 minutes.