During a recent move, I found my WikiReader [0] from 2009 at the back of a drawer. Tossed some new AAA batteries in it and it fired right up. It contains a fairly complete offline copy of (2012-era) Wikipedia and some reference material for survival, medicine, farming, and repair of various mechanical and electrical devices. Remarkable little device for the $20 I paid for it.

[0] https://en.m.wikipedia.org/wiki/WikiReader