I visited Chichen Itza on a day tour from Cancun during the summer of 2005. It is extremely hot so remember to bring a hat! After an hour of listening to my guide with two dozen other sweating people, we were given one hour free time to explore on our own. I spent a large part of that hour waiting in line to go inside the pyramid and I must say I was very disappointed. There was nothing to see inside except for a jaguar throne and it was actually hotter inside the pyramid than outside of it! After that disappointed experience, I had just enough time to climb up and down the pyramid before I had to return to the tour bus. Overall, I very much enjoyed my visit and you should definitely go visit it if you are in the area.