Johnson Space Center in Houston. We took one of the three available tours that included a visit to one of the two former Mission Control rooms that were used during the Apollo program. It is fascinating to think that the total computing power in the room was about the same as that found in a modern day cell phone (at least that is what the tour guide told us). Note also the plastic tubes on the left side of the console. There was no e-mail in those days so if you wanted to send a message to someone else anywhere in the building you sent a note on paper in a tube to them through a system of pipes like those used today in many banks and other businesses! We have come a long way since then but I bet they didn't have the spam problem then that we have now! If you are at all interested in the space programs of both the US and Russia, this tour is a must. There is another tour that takes you into the current mission control room (where they are in communication with the Space Station) but we did not have the time to do that tour as well. We also got to go inside many of the other buildings, including the one that contains the training areas for both the Space Shuttle and for Space Station Freedom.
One of the consoles in the former Apollo 13 Mission Control room