Watch the Chromatic Mission online guitar lesson by Robben Ford from Rhythm Revolution: Vamps & Jams
This is a three chord vamp, just a series of minor triads. Something I enjoy a lot is taking one chord and just moving it around, not trying to play a lot of clever chords. I just like the sound of one chord moving around - Cmin7 to Amin7 to Fmin7. Not only is it simple, but you can virtually play the same thing on each of the chords and you're still getting movement and creating a harmonic statement of some kind.
However, you don't want to just be playing the same thing over and over again, so it's time to resort back to your chord voicings and harmonic devices. This could mean moving around in accordance to the scale, or chromatically, or pentatonically, etc. Let's look at some ways you can experiment with these types of movements, and what they can unlock in this kind of vamp.