Watch the Mighty Melodic Minor online guitar lesson by Shane Theriot from Solo Mojo
The melodic minor scale is a somewhat strange but very useful scale. Just learn 2 positions and you will have a lot of ammunition should you ever need this sound. I often times will use the scale to solo over altered chords. This is done by playing it up 1/2 step. By creating this tension over the 57 chord, you instantly sound like a more seasoned improviser.