Ut Re Mi

 Out of pure insanity, I have installed GNU Solfege.

 Well, Not out of pure insanity — I was researching the penny whistle (An English instrument used in early American anthems and modern Celtic music; it's more commonly called the tin whistle), which, in Wikipedia, linked to the Solfege (FYI, The names of the notes are really Ut, Re, Mi, So, Fa, Ti, and Do — notes and syllables from a catholic hymn). On the Solfege page, there was a link to GNU Solfege, So I downloaded and installed it.
 GNU Solfege is quite an impressive program. It does a number of things, like teaching you basic music theory, training you to recognise harmonies and intervals, among other things. From the site, this is it's features:

• Recognise melodic and harmonic intervals
• Compare interval sizes
• Sing the intervals the computer asks for
• Identify chords
• Sing chords
• Scales
• Dictation
• Remembering rhythmic patterns

GNU Solfege is an amazing program, definitely a must-have for those who have problems recognizing tones or has rhythmic problems.

 I'd write more, but I am too busy messing with the genius LightStep WM.