Hey man, how's your mode?

Back in the period between roughly 1150AD and 1400AD there developed scales called "modes". (Actually deriving from the Greeks some thousand years before.) And since music was centered in the church during that period (I'm sure there was plenty outside the church as well, but we don't have much in the way of records of that period) they came to be known as "church modes".
These modes haven't been used very much for about 500 years, but now many contemporary musicians are using them as a basis for their compositions or improvisations. Listen to any "fusion" musician, such as Donald Fagan or Dave Sanborn or Dave Grusin or Russ Freeeman of the Rippingtons, etc, etc., and you'll hear many of these ancient scales being used.
While these modes can be played in any key, you can get a feel for them by just playing the white keys on your piano at first, noting the relationship of half-steps and whole-steps and listening to the distinctive sound of each mode.
Here are the church modes and their intervals:
Dorian: WHWWWHW (like playing the C scale from D to D)
Phrygian: HWWWHWW (like playing the C scale from E to E)
Lydian: WWWHWWH (like playing the C scale from F to F)
Mixolydian: WWHWWHW (like playing the C scale from G to G)
Aeolian: WHWWHWW (like playing the C scale from A to A -- also known as the A natural minor scale)
Locrian: HWWHWWW (like playing the C scale from B to B)
Ionian: WWHWWWH (Does that look familiar? It ought to -- it's just a major scale!)
If you can't see the score, click here to get the Finale Viewer Plug-In. Produced using Finale.
The thing that makes these modes so appealing and distinctive now is that now they are being used in the context of a harmonic setting -- in other words, with chords in the background. That wasn't the case back in the middle ages -- only melodies were used, and as those melodies interfaced with one another through the use of counterpoint, harmonies were created, but only incidentally -- there was no "tonal center", as there is when chords are used.
So by using these modes to improvise in, along with a chordal background based on more-or-less traditional harmony, these fusion musicians create exciting new sounds by juxtaposing various scale degrees against the backdrop of semi-standard chord progressions.
How can the average piano player take advantage of this knowledge?
By experimenting with the modes in the right hand melody while playing chords in the left hand.
For example, try improvising using the Lydian scale in your right hand. That will mean playing a raised 4th, rather than the usual scale 4th. That will give your improvisation a sound that is certainly different than what we are all used to, but it will also be refreshing!
Try it. I think you'll like it!
Go to page two for a sample improvisation based on the Lydian Mode.
For more detailed instruction on the modes, go to: http://www.playpiano.com/catalog/catalog08.htm and scroll down to Specialized Video Courses and look for: "Scales: All The Modes And Their Fingerings"