If you have a few million lying around, and you qualify, you might want to add a Space Shuttle to your collection: NASA is selling off historic artifacts, and the Orbiters are among the lots:
NASA is inviting eligible education institutions, museums and other organizations to examine and request space program artifacts online. The items represent significant human space flight technologies, processes and accomplishments from NASA's past and present space exploration programs.
This makes perfect sense to me. The Orbiters are large, and expensive to maintain. If NASA keeps them they'd have to find a place to house them, keep them clean, and so on. That would be a huge waste of money! By selling them to a museum or some other institution NASA gets some cash, and a museum gets just about the coolest exhibit ever. I would pay an admission fee to tour through an actual Orbiter! So this is a great idea. If you qualify, go to this page and sign up.
The NASA announcement also mentions Hubble artifacts; I suspect they mean cameras and other equipment removed from the observatory when it was serviced. The Faint Object Spectrograph already sits in the National Air and Space Museum, but several others (WFPC2, GHRS, FOC, COSTAR) may be on the auction block.
I'll note I already own a piece of Hubble: when I worked on the camera called STIS, all the team members were given a piece of mylar insulation blanket that was removed in a 1999 servicing mission as a souvenir. The snippet is encased in plastic, but it flew on Hubble for nearly ten years.
I wonder if it's legal for NASA to sell them? That would be a nice fundraiser too.