I've started working on some of the issues from the GitHub issues tracker, and chief among them is print. I hope to eventually support PDF export, but for now I've got basic printing support enabled and working!
For best results, make sure backgrounds and colors are enabled when printing. This will enable an extra level of color coding just like what's normal on the site, making it easier to recognize each power. You'll also probably want to disable headers and footers, to cut down on unneeded info.
I recommend printing in a non-Webkit browser, such as Firefox or Internet Explorer. Webkit doesn't properly render columns when printing pages, so the site defaults to full width for all of your character powers. However, Firefox and IE will lay out the page using two columns, not unlike the actual 13th Age books.