Wikipedia Founder Jimmy Wales says he's boning up on Ruby on Rails for family reasons. He tells the New York Times that right now he's reading...

...Ruby on Rails 3 Tutorial — a book about Web programming. Ruby is a programming language, and Rails is a whole suite of prewritten software components that you can use to quickly create a highly functional Web site. The original version of Twitter was put together with Ruby on Rails. My 11-year-old daughter is learning to program, so we’re learning Ruby together, and I’m trying to stay a bit ahead of her, so I’m reading the tutorial.

He's not all work, though. Also on his Kindle is Hunting by S. M. Hineline, about war between humans and vampires.