Good luck. I just had back surgery again Monday, so I know how you feel. If you really want to entertain them, talk them into giving you versed early and let them laugh at whatever goofiness you might say.
I'm no stranger to anesthesia. I had 3 back surgeries within 10 days a couple years ago.
Like I said, this isn't really a surgery, they are just putting me to sleep because they couldn't get it numb enough to do a biopsy while I was awake. Believe me, 10-12 shots in the tongue and it still wasn't numb enough to touch, much less take a plug out of.