Yeah, Curtis Rhodes' 'Microsound' is definitely the current be all - end all on the subject, but sort of, er, extensive for first picking up something.
Especially if you're just trying to throw together something to do rhythm work.
That's not to say it can't get really complicated, any algorithm can. There are several different topics or techniques on the subject in terms of getting a 'smooth', realistic sound (see Ableton Live) instead of a flutter-y or clipping, noisy sound (see my software).
Unforunately, I can't think of a single tutorial or example except for Nobuyasu Sakonda's, which has also been recommended.
Do you have the basic idea of what's happening in granular synthesis?
That's half the battle.
I built a pretty easy example with the waveform display and groove~/buffer~ if you'd like to see that . . .
There are lots of interesting Granular things in the max archive - Use Search!
For the rhythm section of you question you could search Google for Nick Collins' BBcut Library - i think you can get it for Csound and definitely for Supercollider - it might give you some ideas of things to try in Max.