I love to crack every joint in my body, and some places that aren't joints.
toes
feet
ankles
knees
hips
back
sternum
shoulders
neck
elbows (I can hyper-extend them, which makes popping them great!)
wrists
hands
fingers
ears
jaw
When we were little, my sister and I used to pull each others' toes to pop them. It was awesome.
(Is that weird?)