rim shots is where you hit the head and the rim at the same time giving you that really loud crack sound.
rim knocks you place the bead (or butt) of the stick, (whichever you prefer and whats best for which grip you use) on the head of the drum. (i prefer about 2 or 3 inches left of center) and while the stick is still toching the head, you hit the rim with the other side of the stick.
A stick shot is when you place the tip of one stick on the head of the drum and hit that stick with the other one - it gives you a more woody sounding alternative to the rim shot. Buddy Rich used this one a lot...
I will describe some that I know. Some will be repeats from above.
Rimshot: The bead of the stick will strike the head of the drum, while the neck or shoulder of the stick with strike the rim at the same time. Produces a sharp, cracking sound. Gunshot effects in shows are made this way. Hitting closer to the neck produces a sharper, quicker attack. Hitting lower on the stick produces a fatter, meaner sound.
Rim-click, Rim-knock: One end of the stick rests on the drum, usually a few inches from the center, and the other end portion of the stick is used to hit the rim. Produces a wood-block like sound, like a knock on the door. As a rimshot, the stick placement affects the sound.
Stickshot: The bead of a stick is placed in the center of the head, and held firm. The other stick hits hard on the placed stick. Produces a more woody sounding shot, less defined.
Smackshot: A rimshot on both hands at the same time.
Splitshot: Same as Smackshot, only split between two different drums.
Slap: A rimshot with the hand. Cup the hand, and bring it down on the drum, the tips of the fingers hitting the head near the edge, the fleshy palm area hitting the rim. A slight discomfort with arise, but it can be avoided if one finds the right spot to hit the drum. A bright poppy sound is produced.
Skank: A rimshot quickly dampened with the hand. Only works well with a high amount of overtones on the head to dampen.
Stick Pop: Rest the bead of the stick on the head. Then, bring the stick down, as if to lay it on the drum, and strike the rim, like a rimshot. However, keep moving the stick, so the bead of the stick will pop upward, the fulcrum of the stick being the contact point with the rim. A little pop sound will be produced.
Stick Kick: This is a fun one. Rest the stick on the drum with about 3-4 inches of the stick hanging over the edge. Now, with the other stick, come up from below and sharply strike the stick, and continue going up. The stick on the drum should make a loud pop on the drum and fly upward, spinning. Now just catch, and you got a pretty nifty trick.
Rim Roll: A one-handed roll method. An advanced technique. Hold the stick parallel to the drum. Let it drop as a rimshot, and follow through like a stick pop. However, this time you will snap your hand shut around the stick, still contacting the rim, and the bead of the head will come down on the head a second time. Repeat this procedure, balancing the stick on the rim. For the first tries, rimshots will sound. After practice, they'll be gone.
"clap" effect - cross stick with the left, then another stroke a split-second after with right on the left stick (like a flam) - can also be used for some other effects by playing the flam wider and the 2nd note softer ("echo") and/or playing multiple notes (decreasing volume) with the right on the left stick.
I think those were from Lil' John or J.R. at a PASIC a few years back?
"buzz stick shot" - same as stick shot (above) except left stick buzzes onto the head little longer before the right hand's stick shot - produces a "zzzOCK!" sound...
these are so difficult to describe with words.....