I don't know what the name of this drill is but Don Alexander, Michigan Volleyball Registrar, taught it to me. Call it a digging drill if you want.

You have three players. Two (A and B) are spaced an equal distance apart with the third player, who is a digger, (C) next to one of the two.

The drill starts with A spiking the ball at C (who is positioned next to B). C bumps the ball to A. Immediately after bumping the ball to A, C runs next to A and turns 180 degrees. A sets B and B spikes the ball at C. C bumps the ball to B and runs next to B (after turning 180 degrees). B sets A and A spikes the ball at C. This continues for as long as you desire.

The keys are C is always digging. Whoever C digs to (A or B) sets and the other spikes at C. A and B are either spiking or setting.