Well, since this is the kind of thing you can't discuss with a lot of people who know you IRL, I'll post here!
My colonoscopy was yesterday. I had an "incomplete prep" issue 5 years ago and was determined to have an effective prep this time. I stopped all the high-fiber stuff I LOVE (fresh vegetables, dried blueberries, nuts, whole grains) Saturday and Sunday. That part, I swear, was the worst. It's like you have to suspend all good eating habits. The main component of the prep was a brand of polyethylene glycol, which was OK mixed with Crystal Lite except that I got chilled from drinking cold beverages almost constantly for 3 hours. I finished at 8 PM, which is what the directions specified, and nothing happened. I followed the noxious stuff with a chaser of good scotch to get the taste of Crystal Lite mixed with PEG out of my mouth. Finally, at 6 AM the effects manifested themselves- one hour before I had to leave for the appointment. Fortunately, it was effective.
This was not the doc who had done my previous ones without anaesthetic (my preference); previous doc's office couldn't tell me what it would cost under my high-deductible plan and I gave up. My primary doc had recommended this guy, who really preferred to use anaesthetic. His explanation was rational and not based on the "I'm the doctor and I'll tell you what to do" attitude; he said that he really preferred to navigate as he needed without the constraint of trying to avoid pain to the patient.
It worked out well; they did find some nasties but I don't have to come back for 5 years, so they're not very exciting nasties. The anaesthetic wore off quickly. After relaxing and finally eating real food, I felt well enough to do my regular workout at the gym. They'd advised against it but they also said don't drink alcohol for 24 hours and I had my usual nightcap, too. I'm happy to report that I've survived both in good shape.