Theora is a project mainly written in Ruby, it's free.
Music theory study aid
Theora is a simple Ruby script to help learn music theory. It has two modes: full scale and individual note.
In full scale mode, the program prompts you for a scale, which you are to say out loud and then hit enter. If you get the scale correct, you won't be asked for it again until you've gotten all the scales correct.
In individual note mode, you'll be given a scale and a position ("F#, position 5"). You'll enter the note (in this case, "C#"), and the program will tell you whether you got it right.
You can choose either of these modes at startup, or choose to have both types of question presented to you at random. Please feel free to fork and improve.