Wow! I can't believe this place exist, either. I've been cracking, popping and clicking for so long, but couldn't imagine there was an actual forum for others who do the same. In fact, I am having some difficulties sleeping tonight because I can't seem to pop my lower back and sternum, and thought I'd go online to look for some suggestions.
Where do I crack?
1. Sternum (not always successfully, but keep at it)
2. Lower back (leftside)
3. Big Toes (large joints, but no bunions; right foot most habitually: started after I fractured my foot about 25 years ago)
4. Nose (clicking/popping)
5. Little fingers only (finger cracking freaks me out a bit)
Sternum - aside from my most tried and true techniques – stretching my arms upward, thrusting my chest outward, 'hanging' from a door frame, crossing my arms and getting someone strong to lift me a bit, etc. -- I've developed an 'escalator technique': when I step onto an escalator going down, I let the first step go down one step from the top, as grip onto both sides of the railing. As I de-escalate, I pull my body up slightly, creating a 'dropping' technique that allows my body to stretch and usually pops my sternum and sometimes by lower back. My feet never leave the step. It feels wonderful 
. My favorite escalators are at Virgin record stores. Why? Because they tend to be narrower, providing just the right amount of space to keep more arms closer to my body and more fully distend my arms as my body drops (ever so slightly), and my sternum pops. Also – especially since I don't have an escalator (yet) at home -- a good massage into tense muscles under my shoulder blades provide a good deal of relief and often allow me to easily keep popping my sternum for a few days afterwards.
Lower Back: a lot of tightening, twisting, contorting, pressure point massaging. I love deep tissue and shiatsu massage, and these usually provide relief. Ihave one of those portable seated massage pads for my back - upper, lower, fullback settings. Instead of placing it on a chair, I will sometimes place it on my bed, lay down on it, aligning correctly so as not to have it actually massaging my spine, but making certain it relieves muscle tightness, which makes it easier for me to crack my sternum and lower back. Even my toes seem to crack more easily.
Toes: when I am without shoes, I am constantly tightening and extending and flexing my right big toe to crack. I love a cold floor. I can crack pretty loudly. When laying or sitting, I tend to use the ball of my left foot and rub/push against the joint of my right toe until it cracks. Or, I just constantly de/flex my toes until they crack. Other techniques: lay on the floor or on my bed, with my feet facing the the wall, place my feet (with socks on) against the wall, then press or stretch my toes against the wall as if I was standing on my toes until the pressure releases and they crack. Last thing: gentle deep knee bends, raising the balls of my feet, so that I am 'standing' on the bend of my toes. Great stretching.
Nose: I tend to pressure point the tip of my nose and rub/twist around the cartilage until it pops. I don't do this often, and never in public or in the company of others as I belive to be rather unattractive. Feels great, but unappealing.
Little fingers: Not very often. But when I do, it is a simple snap, crackle, and pop.