How It Sort of Works:
It's probably not very surprising that science has been unable to locate chi energy on any X-Rays. What might be surprising is that despite this, actual scientific studies that don't involve a single "spirit crystal" show that acupuncture actually freaking works. Yes, according to that article in The Wall Street Journal, "neuroimaging studies show that it seems to calm areas of the brain that register pain and activate those involved in rest and recuperation," all of which sounds surprisingly official for a pain-relief method that involves repeated stabbing.
That's actually one theory on how it works. When an acupuncturist sticks a tiny needle in your skin and twirls it around, she's not quite harming you enough to cause real pain, but she is harming you just enough for your body to act in self-defense and release a natural chemical called adenosine, which acts like a local anesthetic.
Those aren't man-boobs, they're chi-sacks.
As a side effect, you also experience relief from whatever else might be ailing you. Of course, this doesn't mean that the process is actually healing you, but it has been shown to treat some pains that Tylenol can't help with. Which is why the world's best hospitals like the Mayo Clinic and Duke University Medical Center now offer acupuncture. Still, most doctors agree that as a general policy, you shouldn't attempt to cure diseases by stabbing them.