When you're over fifty, there are certain preventive-maintenance procedures which your doctor recommends. I'm only running about five years late with this one, but after hearing all the stories, I ran out of excuses.
According to Wikipedia, a colonoscopy is:
... the endoscopic examination of the colon and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis (e.g. ulceration, polyps) and grants the opportunity for biopsy or removal of suspected lesions.
Now, if that doesn't satisfy you, the U S National Institutes of Health released NIH Publication Number 10–4331, which gives you the lowdown. Click here.
My procedure is tomorrow. If you don't have anything better to pray for ...