Use pentatonic scales to build guitar solos. Once you have mastered how to play them in the different positions, pentatonic scales can help you create solos quite easily in the proper key. Of course, you probably won't want to just play a straight pentatonic scale, but knowing the notes you can use is a great head start.
Use pentatonic scales to practice an instrument. Whether you are a piano player or a guitar player, it is important to practice your scales on a regular basis. Keeping your knowledge of pentatonic scales fresh is not only useful for real-world writing situations, but also to keep dexterity at its peak.
Write vocal harmonies using pentatonic scales. Pentatonic scales are usually discussed in relation to instruments, but they can be also be used to write vocal harmonies. As long as you know the key of the song, you can write vocal harmonies using a keyboard, guitar or voice. While many lead vocal harmonies are fairly apparent in many types of music, you may need to use scales to write interesting backup harmonies.
Use pentatonic scales to aid in improvisation. This is an especially important use for jazz, rock and blues musicians that often do not have completely set parts. Without a firm knowledge of the pentatonic scale, it can be difficult to know what notes can be played. While some notes may work better than others in certain songs, any note in the pentatonic scale can be used in the right key most of the time.