Stevens continues to be busy off the Supreme Court. How are the other active and semi-retired (Souter and O'Connor, especially O'Connor, still hearing lower court cases from time to time) justices doing in such a context? They all in some fashion, including speeches, seminars and other projects, find stuff to do. O'Connor is the most busy, perhaps, serving on lower courts and promoting civics education. Souter has voiced the importance of civics too (and history overall) and has been a bit more public in the last few years, including in a rightly praised Harvard commencement address that nicely criticized the critics of the "living Constitution" model.
Scalia and Breyer just was in Congress to talk about what they do, each (even if Scalia doesn't like recording) often giving speeches or talking (Breyer has been on various media outlets) about their judicial philosophy. Breyer wrote his own book a year or so ago, recommended, and still seems to be promoting it. Is the paperback out or something? Scalia co-wrote a book on advocacy; he is celebrating his twenty-five years on the Court (unlike O'Connor, doubt it will be a sign of retirement). Thomas wrote an autobiography and I recall that Sotomayor was in the process of writing one (or helping with an authorized version). Online you can also find more than one Q&A she had in various fora. She has said that she believes her involvement with the public at large is a major part of her work.
C-SPAN also had remarks of others, including Kennedy, who a few years back had some seminars for young adults. Roberts got a mention when he dissed law review articles; I was inspired to buy a four justice stamp set he announced a few years ago. If you go to the Supreme Court's speech page, Ginsburg dominates, with a few by others sprinkled in. I don't hear to much about Alito, though he was seen at a right wing event. Kagan answered some questions at the Aspen Institute.
And, Thomas will teach a seminar on constitutional law. I have a couple volumes on my own view of constitutional matters among other musings around here and elsewhere. They are about as aspirational (that is, as compared to the law in place now) as his version, though he has a bit more pull. From the one or two times I saw video, he seems pretty comfortable with law students. Does he show pics of his R.V.? Stevens interestingly specifically rejects his views on certain subjects, suggesting how personnel plays such an important part in constitutional law. After all, it is not as if Thomas is alone in his views on the subjects discussed, though again, how far he takes things is rather unique.
They also are interpreting constitutional law.