I can crack my fingers (i just twist them side by side), my knuckles, my wrist (up & down), a joint in the middle of my head, my neck both ways, my elbows, my toes, my big toe (side by side)my knees, and i can pop my pelvis/hip bone.

Ah yes, this used to happen to me when i would run a lot. I would lean forward and they would pop or adjust themselves. It felt good but i dont get them as much mostly because im unable to exercise due to health issues.

Actually i have been able to crack something in the middle of my hand. I cant crack it a lot but there are rare times where i can crack it 3 times a day. Although i dont recommend doing it that many times a day since my hand has gotten a lot of pain from it. It feels good though!