When I travel, I do lots of reading. It fills in time on planes and trains. Although I like paper books, my reading when I travel is all ebooks.
Here is a great discovery—free, classic, out-of-copyright books in high quality ebook format:
Standard Ebooks is a volunteer driven, not-for-profit project that produces lovingly formatted, open source, and free public domain ebooks.
Ebook projects like Project Gutenberg transcribe ebooks and make them available for the widest number of reading devices. Standard Ebooks takes ebooks from sources like Project Gutenberg, formats and typesets them using a carefully designed and professional-grade style guide, lightly modernizes them, fully proofreads and corrects them, and then builds them to take advantage of state-of-the-art ereader and browser technology.
Check out the website.