Serve

Setting up for an overhand serve.
A man making a jump serve.A player stands behind the inline and serves the ball, in an attempt to drive it into the opponent's court. His or her main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly. A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent.

In contemporary volleyball, many types of serves are employed:

Underhand and Overhand Serve: refers to whether the player strikes the ball from below, at waist level, or first tosses the ball in the air and then hits it above shoulder level. Underhand serve is considered very easy to receive and is rarely employed in high-level competitions.
Sky Ball Serve: a specific type of underhand serve occasionally used in beach volleyball, where the ball is hit so high it comes down almost in a straight line. This serve was invented and employed almost exclusively by the Brazilian team in the early 1980s and is now considered outdated. In Brazil, this serve is called Jornada nas Estrelas (Star Trek).
Line and Cross-Court Serve: refers to whether the ball flies in a straight trajectory parallel to the side lines, or crosses through the court in an angle.
Top Spin: an overhand serve where the ball gains topspin through wrist snapping. This spin causes the ball to drop faster than it appears to a passer receiving it.
Floater: an overhand serve where the ball is hit with no spin so that its path becomes unpredictable. This type of serve can be administered while jumping or standing. This is akin to a knuckleball in baseball.
Jump Serve: an overhand serve where the ball is first tossed high in the air, then the player makes a timed approach and jumps to make contact with the ball. There is usually much topspin imparted on the ball. This is the most popular serve amongst college and professional teams.
Jump Float: This is a serve like the jump serve and the floater. The ball is tossed lower than a topspin jump serve, but contact is still made while in the air. This serve is becoming more popular amongst college and professional players because it has a certain unpredictability in its flight pattern.
Round-House Serve: the player stands with one shoulder facing the net, tosses the ball high and hits it with a fast circular movement of the arm. The ball is hit with the palm of the hand, creating a lot of topspin.
Hybrid Serve: An overhand serve delivered similarly to a top spin serve; however, it has more pace than a floater, but has a similar unpredictable path.