I find one of the coolest things to play around with on the guitar is the number of natural harmonics that can be found in many places. These sounds are enhanced much more when you add distortion, and you can get some really cool sounds.
If you have never played a natural harmonic before, they're pretty easy once you get the hang of them. To summarize quickly how to play these natural harmonics, you're going to place your finger directly above the fret wire (not in between frets, as you would do to normally play a note). The key is to not actually push down on the string, but to touch the string lightly, and then pick. Once you have picked the note, you will get much more sustain if you release your finger from the string as opposed to keeping it in place. The easiest spots to get natural harmonics are above the 5th, 7th, and 12th frets (they can be found above many other frets as well, but these are the easiest). If you have an electric guitar, using distortion will bring out the sound much more.
If you want to utilize natural harmonics in a useful way, this lick should help give you some ideas of how you can use this skill and apply it to your own creations. Even if you can't play this lick up to speed, you'll be able to see what's possible with this technique.
Check out the video below, and the tablature directly underneath.