I would be very surprised if you haven't heard of the infamous street artist known only as Bansky. Dismaland was a temporary art installation comprised of artwork by Banksy himself and 50+ others from around the world.
I was originally putting off going to Dismaland because I thought I had seen all there was to see in pictures online. However, I know first hand that pictures don't always do something justice. As it turned out, every little detail was thought of and executed to make the whole experience something special and truly unique. The only problem was the relatively short timeframe you get to enjoy it - leading to rushing around to see it all. I definitely would've preferred to make a day out of it, but I am pleased to have gone and would happily pay the additional £20 per ticket on ebay again. The self-described "bemusement park" was one of a kind and really quite surreal - hopefully you can get a sense of it from the photographs below!