They had computers in one place I was in, but not connected to the Net, just for doing some basic word processing and typing tutorials.

I found the C# compiler that is hidden several levels deep by default in the Windows directory and decided to teach the other prisoners how to code. I needed some reference materials as it's really hard when you have no docs and literally just the compiler. They don't allow computer books in most places "for security reasons", but a very elderly nun took pity on me and asked me what I wanted. I told her "C# Weekend Crash Course" (I wasn't a C# dev at the time and it was the only title I could think of) and she bought it off Amazon and smuggled in not only the book but the CD-ROM that came with it, bless her. I managed to teach the guys how to write text adventures which they enjoyed. I couldn't think of what else fun I could get them to do with only console text in/out.