Haven't thought about it, but I guess I'll give it a crack:

Many, many finger knuckles
Thumbs
Wrists
All toes, probably all joints in all toes
Ankles
Knees
Neck, frequently and most often specifically to make non-crackers cringe
(yes, I called myself a cracker; if you have a problem with that I'll come down off the porch and fight you, just as soon as I finish eating my possum and drinking my mason jar of corn liquor)
Back (upper, middle and lower)
Nose, as a novelty
Shoulders
Hips (thought I'd lost it but I just did it by accident trying to crack my knee)
Sternum, but always unintentionally

…and when I can do my eyeballs, I'll let you know.

I've never heard of anyone besides my cool, former self popping their hips. I could do it back in high school when I was a runner and stretched out all the time, but I've really lost the knack. As I am in a public place at the moment, I cannot test your newly-discovered method, but as soon as I'm home and in the privacy of my own room, I shall try it out.

And I salute you in advance.

Mostly they seem to think we're actually breaking or eroding bone or something ridiculous like that. At least, that's the impression I get. I suppose the more educated of them think it's the ligaments or tendons that are snapping, thread by thread. Very few believe the whole knuckle-fluid-bubble-popping theory (which I staunchly adhere to).

Ever since my joint-cracking idol in high school viciously cracked his neck, causing me to spend hours (and every one worth it) learning to crack mine too, my favourite gross-out has been cracking my neck with my mouth strategically open so as to make the sound reverberate. However, back in those high school days, when I was a runner and stretched out all the time, I could do that special thing that would nearly gross me out…I'd crack my hip-joints. How have the mighty fallen...