holy shit, that sounds awesome. I need to google that.
One really cool thing to do is if you have a fairly boring chord progression, just figure out which chords are dominant, tonic, or subdominant and substitute them with other chords of their type. And try adding sevenths here and there to see if they sound good.
Did you get into anything like Augmented 6th chords or secondary dominants?
oh wait, is an augmented 6th chord just an augmented chord, or something else?
I'm exploring the diminished scale recently.
Augmented sixth chords are chords like the French, Italian, and German sixths. Some debate an inversion of I think the German one to be English sixths, too. They're used as predominants and built as following:
b6, 1, #4
In c: Ab, C, F#
b6, 1, 2, #4
In c: Ab, C, D, F#
b6, 1, b3, #4
In c: Ab, C, Eb, F#
Generally speaking, they're really hard to use and still sound good, I think, but if used correctly, you can do some crazy stuff with them - notonly use tem as predominants, but modulate to wierd keys and things. If you're just going for a variation of a predominant, though, I'd use a neapolitan (a major chord built off the minor second degree).
And secondary dominants are simple. It's basically just going outside of the key for only a few chords...
Say a I IV V I progression...
Adding a secondary dominant looks like this:
I IV viidim/V V I
The vii/V is a secondary dominant. (V and vii are most common in dominant positions)
Say you're in C major - the original progression is C F G C. How you get the secondary dominants is like this: viidim/V - look at the bottom, V of C is G. Now, you take the viidim of G. That gives you fdim. So, your chord progression is now C F fdim G C. That's just an example. And secondary chords aren't always held tom dominants. You can find plenty of stuff that does progressions and cadences in secondary keys.
Anyways, I guess you could've just googled it...