Writing your own e-books is useful
Before our recent trip to Poland I took the time to create my own e-book, containing the names/addresses of people to whom we wanted to send postcards.
Authoring ebooks is simple, and this was a useful use. (Ordinarily I'd have my contacts on my phone, but I deliberately left it at home ..)
I did mean to copy and paste some notes from wikipedia about transport, tourist destinations, etc, into a brief guide. But I forgot.
In other news the toy virtual machine I hacked together got a decent series of updates, allowing you to embed it and add your own custom opcode(s) easily. That was neat, and fell out naturely from the switch to using function-pointers for the opcode implementation.