NASA completed a small step toward the transition of the Space Shuttle era to that of the Constellation rocket era: the handoff of launch pad 39B.
While Atlantis was launched on pad 39A to service Hubble, Endeavour sat on 39B in case it was needed for a rescue mission. Endeavour was rolled to 39A on May 31, leaving behind 39B which will never be used to launch another Shuttle.
Launch pads 39 A and B were originally built to launch Saturn V rockets to the Moon. They were then modified to be used by the Shuttle. 39B was first used for the ill-fated Challenger launch in 1986, and the last launch from that pad was in 2007. It will be modified for the Ares rockets being built now as part of Constellation.
I know it's just a launch pad, but it does signal the first notable sign of the beginning of the end for the Shuttle. This has special meaning for me, too. See that picture on the right, in the sidebar of the blog? It's me in front of 39B. I was there in 2002 for a meeting, and we got to tour the complex. We got pretty close to the pad, and you can see the orange external tank and the tops of the two solid rocket boosters peeking over the service structure.
It's not terribly skeptical to feel attached to a piece of hardware, but there is still some atavistic piece of us that does so anyway. And this is an important transition in the history of NASA, from one major transport system to another.
And, of course, 39B isn't going away. It's being transformed to aid yet another generation of rockets and explorers, helping them to extend our boundaries and go on the grandest adventure of them all.