Major Pentatonic Scale on the Bass Guitar.
Of all the bass scales, the major pentatonic is the one mostly used in rock and popular music. If you learn this scale in two octaves in all keys you'll never have a problem coming up with a bass line in any kind of jam sesssion.
See this lesson on playing Sir Duke and you'll quickly see what I'm talking about.
I have included 2 fingerings with this scale...
Use the first fingering for practising, it's a great one to master because it teaches you how to get from the bottom of your bass to the higher register very quickly and accurately.
This next fingering is the one I use most when I'm playing.
Learning this is a must for all you rock players who want to get away from just playing the Tonic all the time, but don't want to go too far away from the chord.