My latest videos lesson on YouTube introduces the Cycle of Fourths.
I think its a very valuable piece of theory to understand, as movements of a fourth are used countless times in music.
It's also a great tool to use for practicing anything new, wether it be a Chord, Arpeggio or a new Scale. Playing it over the Cycle of Fourths will help familiarise yourself with it on the fingerboard.
Check out my video here: http://bit.ly/cycle4ths
Let me know what you think