I just learned on the gamebook mailing list that the wonderful Time Machine series of interactive books has been re-released in eBook format. Although aimed at children, these are among the most effectively-written and interesting of the many “Choose Your Own Adventure”-type books released in the eighties. At $3.99 each, the new electronic editions cost twice as much as the original paperbacks did, but it’s still a pretty good deal if you want to relive your childhood adventures or learn about history in a game-like manner. The series can be purchased at Amazon.com and several other sellers of eBooks.