WikiReader

WikiReader is a portable device containing the entire contents of Wikipedia, stored directly in it so that network access is not necessary. The content can be updated by download or MicroSD card. An article about it calls it a "$10 device", though the price has varied from $10 to $29 over time.

Links

 * Official home page
 * Article about it
 * Product page on Amazon
 * Official source code for the WikiReader
 * WikiReader HHGTTG ROM flash changes the power on splash graphic to a Hitchhiker's Guide to the Galaxy Theme