Continuing the quest for new sounds lets take a look at Aeolian b5. This the 6th mode of Melodic Minor. This mode is just as it sounds, a minor scale with a flat 5(hence the name). This mode can be used in place of the standard minor scale and just gives you a little different flavor. The great thing is, once again you've introduced a new "parent" scale and can draw on some of its harmony to superimpose over a minor chord.
Lets say for example your Rockin over on Am7 chord and you want add a little spice. Try superimposing an Ebmaj#5 over the top of that chord. This will certainly bend the ear a bit but that's the whole point! The parent scale in this case is C melodic minor(the relative major scale turned melodic minor). If you harmonize this scale you will certainly end up with an Ebmaj7#5 chord as its b3 chord. It's is really close to a standard minor blues scale in the application but I promise you it does not sound like a typical blues scale. How long you stay in this mode is up to you of course but I usually just mix it in here and there and it makes for some interesting lines.
One more example is to simply play a Cmin/maj7 arp over your Am7 chord. This is the 1chord in C melodic minor and should also highlight the b5 tone against the Am chord. Lots of possibilities here but I think you get it. That's all for now but check back for some more nuggets and please feel free to leave comments or questions! Make sure you check out the new Bleeding Harp tune "Live to Ride" now available on iTunes! Cheers!