Our website provided a free download of Sebastian 100.0 for Mac. This Mac app was originally designed by Dr. Jonathan Crosmer. The program belongs to Education Tools.
From the developer:
Sebastian is an ear training tutor that gradually increases in difficulty.
Many music students struggle with ear training, though it is a critical skill for musical development. The most effective learning method is one-on-one instruction with a tutor, at the piano. But ear training is a technical skill; the main thing the human tutor provides in this area is a stream of problems, adjusting to the student's proficiency.
You may want to check out more software for Mac, such as Jewel Quest Mysteries: The Oracle of Ur, shootShifter or FoldingObserver, which might be related to Sebastian.