Comet Jack is not just for modern e-book readers any longer.
Actual, physical trade paperbacks are now available, featuring 248 real paper pages, Phineas's incredible cover, and that new book smell!
You can find them for sale here:
These definitely look cool sitting on the shelf. (I am clearly biased, though. Please judge for yourself.)
And, of course, Comet Jack is still available for Kindle and Nook, for only $2.99!