Watch the The Blues Box online guitar lesson by Rob Garland from The Guitarist's Pentathlon
Here's an application I call "the blues box" which is just shape 2 of the minor pentatonic scale played only on the G, B & E strings. The purpose of this box is to put the focus on phrasing. By using 1/4, 1/2, whole and 1 & 1/2 step bends extra "in-between" tones can be found which are a signature of electric blues playing. Only dogs can hear some of them which is why so many blues tunes feature a dog in the lyrics.