Euwww, got this from something on MSN about knuckle cracking:

The sound you’re hearing is actually two sounds (researchers put microphones up to knuckles to confirm this). The first sound happens when you pull your joint and create a bubble. The second sound is the bubble popping. Joints are where two separate bones meet. Ligaments and connective tissue hold them together, in kind of a bath of thick fluid. When you pull apart a joint, it creates extra space for the fluid. So, that first bubble forms. When the bubble appears, the liquid pushes back on the ligaments, snapping them back into place.

:O I didn’t take any course on the human body; I didn’t know there was a “thick fluid” between joints. It’s things like this that make me not want to move … *coughweirdcough*

My thumb knuckle hurt for the longest time today. :( After math. :b