Goonswarm (GSF, now The Imperium) hosted an event where we were permitted to visit a National Guard installation and check out some tanks.  This was a day long event which I went to and took my son to as well.  It was a long drive to get there and back (Twin Falls, ID to somewhere in Oregon (I've forgotten where)), but was well worth it and we had a great time.  Not only did we get to look inside the tanks, but also got to drive around in one toward the end of the day.  I didn't have a very good camera at the time, and of course no pictures were allowed to be taken inside of the tank for security reasons.  None of these videos are mine, although I'm not sure who in GSF went to the event and posted these.  The pictures of the event are here.  About half of those photos are also not mine.