Every year they put on an ice castle attraction, putting color changing LEDs inside the ice, and let dripping water create huge ice sculptures. The colors seen here are not bumped up in photoshop (in fact I had to lower sat/hue in some because they were getting blown out). You can walk through and under these massive ice formations which are constantly changing colors.
Photos taken with a 5DmkII and 50mm f/1.4
I wish I had gotten wide shots showing how big these were, but I was more amazed by how the ice literally GLOWED with vibrant and changing colors. Here is an example of what the place looks like:
(photo via icecastles.com)