Yes, I voluntarily visited a Thai Prison.

In a guest house we stayed in there were several notes on the wall about visiting a prisoner in a Bangkok prison. They talked about how interesting he was, how to get there, etc etc. We decided to see what it was all about and take advantage of the rare opportunity for such an unusual experience. Two other people from my orientation wanted to join, so there were four of us total. It was definitely worth the trip as we were allowed to actually go inside the prison and speak for awhile with this guy about what it was like. Long story short, what we saw didn't look too bad. It was lush and green just like everything else in Thailand. I'm sure a day in the life would not be so nice, though. I'm sure it'd be absolutely horrific. This prisoner was from the UK and has a life sentence drug trafficking. From what I understand, Thailand will expedite you back to your home country for every crime except the former, as they believe western countries do not punish severely enough for this. 

These people have to pay for everything in prison - their food, their cell, their clothes, etc. This is part of why they want people to come visit them (aside from obviously taking time from the monotony that is their life). They want people to send things. No thank you.

At first it was interesting to listen to him and get some information about what it was like, but I became increasingly more disenchanted, because I just couldn't find it within myself to feel sorry for a criminal. We're not exactly sure what he did, and it's not relevant. In Thailand, tourism is just too important for them to be locking up foreigners who aren't involved in something they shouldn't be. 

It was a memorable experience, as not many people can say they have visited a Thai prison, and the journey to get there and back was an adventure in itself. It was a perfect example of the way their system works. Our directions were "take a boat, get off at stop, pass two 7/11s, prison on left". Obviously there were some specifics that are completely irrelevant to the story. Umm, what??! No, it was not that simple. To check in they send you to this room, back to this room, and then back again, because there is no central system within the country. They can't even pick up the phone and say we've already done something. Once we finally got in we waited for a good half an hour without a clue what we were doing. Finally, we found the guy we were supposed to talk to, only an hour and a half behind schedule. Sounds about right.

For me, the journey was much more worth while than the actual visit. He was a criminal, and I couldn't get past it (although I will admit a seemingly very friendly criminal). But, the experience was definitely something worth writing home about :).