When court's not in session, you can sit in the actual Supreme Court courtroom for a 30-minute intro to the court, the justices, and the architecture of the building. Just line up in the lobby, easy peasy.

Security is weird about photos: you can take pictures standing at the doorway of the courtroom, but not inside? And don't try to take a bottle of water or any snacks into the building. It can't be in your bag, but it can be in your belly.