Solfege is free music education software.

Use it to train your rhythm, interval, scale and chord skills.
Solfege - Smarten your ears! 

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 

TiMidity++ and freepats are recommended packages to install before building 
solfege.  Both have SlackBuilds found at SlackBuilds.org.