If you've never been to Medieval Times, then yes -- you should go. It's something I've always been intrigued by and had the chance to go to a friend's birthday party. Everything was a new experience, and it did bring me back to being a kid who was into knights and dragons.
I'm easily entertained, so getting beer in gigantic plastic cups and watching a hawk terrifyingly circle people's heads is a fun experience. The food wasn't nearly as bad as I thought it would be, and alcohol paired with jousting is a winning combination.
The second time I went here -- not so much. I knew the script they act in front of you (minus the ad-libs) and what to expect in general as far as entertainment. Once you take that out of the equation the whole thing is kinda boring. And you realise the food might not be as good as you remember it. I also found the second time around I paid attention to the prices more closely -- it's not cheap!
Overall, I have to recommend Medieval Times to anyone thinking of going. I highly suggest going with several other people to make things more fun. Certainly not a place to go frequently -- maybe once every few years.