Here is my music-nerd-epiphany post for the day:
You know how, in *minor* blues, the b5 note of the chord can be used in the scale for improv and etc...?
And you know how, in *major* blues, the minor 3rd of the major 1 chord can be used?
Using the b5 in minor has always made sense to me, but I've never been able to fully accept the use of a minor 3rd over a major chord as a viable note to use (still sounds cool, but I've never been able to explain it other than a #9).
But get this, the minor 3rd in major, is the same note as the b5 in the relative minor key... So F natural (minor third) in the key of D major, is the same as F natural (b5) in the relative key of B minor.
I can't think of any practical application for this knowledge off the top of my head (or the middle of it for that matter), but that's what makes it nerdy and cool...