(with some beamer bells and whistles, by a Keynote refugee)
Create notes in the notes/ directory, on the model of classnotes.md. Then generate a PDF of slides with
make -C slides classnotes.pdfslides/classnotes.pdf is the result on my system.
(Of course you can also cd slides; make classnotes.pdf, but I feel more like a command-line master if I use make -C from the top-level directory.)
If you have Keynote and want to use it as a presentation PDF viewer, install PDF to Keynote and then do
make -C slides classnotes.keyTo generate notes (note pages interleaved with slide pages):
make -C notes classnotes.pdfnotes/classnotes.pdf is the result on my system.
I like to print these 4-up in landscape. To generate this format:
make -C notes classnotes-4up.pdfTo make all slide and note PDFs at once, use make all by itself from the top-level directory. (One feels even more of a command-line master when one uses $(MAKE) in a Makefile).
(To get all the keynote files, try make all_key, but no promises: my little AppleScript for running PDF To Keynote may not work quite right in that case.)
I discuss how the bits and pieces work together, and the rationale for doing this, in a blog post: "Easy Lecture Slides Made Difficult with Pandoc and Beamer."