Satriani
I came across a very cool way to get out of the box when playing rhythms. Alot of my students seem to get hooked on a certain rhythm, and stick to it, so in order to get them to experiment with different kinds of rhythms, this is an excellent way of doing it.
Take a blank piece of paper (or use guitar pro if you're that way inclined) and write out 16 16th notes. All we're doing here is creating one measure (bar) of 16th notes. Do NOT connect them as you normally would, but rather draw each on in separately with it's own flags. Now take an eraser (forgot to tell you to use a pencil ?) and erase between 3 and 6 of the notes RANDOMLY. Now just pick that rhythm out on an open string, and see how it sounds. Once you can play it perfectly, apply it to any licks or riffs that you already know.
Obviously, that same rhythm as cool as it may be, will start sounding boring, so do the same thing over again, and draw another 16 16th notes, erase randomly, and then play the 2 measures one after another. Do this 4 times and see how you will instantly have come up with rhythms you might not normally have thought of ?
Have funnnnnnn!!!!!!!!