Basketball - Rules | Sport Rule Changes

Rules

The game is played 5-on-5 with each team having 5 players on the court
Players must dribble the ball while moving with the ball; they cannot travel or carry the ball without dribbling
Players have 10 seconds (8 seconds in the NBA) to cross the frontcourt or shoot once the ball is inbounded
A held ball or "tie up" results in a jump ball
Personal fouls include illegal contact impeding the progress of an opponent; shooting fouls occur when contact affects a shot attempt
Players foul out after 5 personal fouls (6 personal fouls in the NBA)
Substitutions can be made by either team after the ball becomes dead or during timeouts
The shot clock requires a team to attempt a shot within 30 seconds (24 seconds in the NBA) of gaining possession

Traveling - Taking more than 1.5 steps without dribbling the ball
Double Dribble - Picking up the dribble and then dribbling again without losing possession
Out of Bounds - Touching or crossing over the boundary lines results in turnover
3 Seconds - Offensive player staying in the key for more than 3 seconds without actively guarding
5 Seconds - Offensive team failure to advance the ball over the halfway line within 5 seconds
8 Seconds - Failure to move the ball to the frontcourt within 8 seconds of gaining possession
Kicking - Intentionally striking the ball with the foot or leg
Goaltending - Touching the ball on its downward trajectory to the basket or directly over the cylinder
Basket Interference - Touching the rim/backboard/ball while ball is on the rim or within the cylinder
Lane Violation - Offensive player entering the lane before the ball is released from a free throw
Backcourt Violation - Offense returns ball to backcourt once it is established in frontcourt

Personal Foul - Illegal contact against an opponent such as pushing, holding, blocking, charging, etc.
Shooting Foul - Personal foul committed on a player in the act of shooting; results in free throws if shot is missed
Reaching In - Extending arm(s) and making illegal contact while defending
Blocking - Illegal contact using one's body to impede the progress of an opponent with the ball
Charging - Offensive foul where offensive player illegally runs through defender who has established position
Holding - Illegal use of hands, arms or body to inhibit an opponent's movement
Illegal Use of Hands - Pushing, hitting or slapping the ball handler or shooter outside legal guarding position
Flagrant Foul - Excessive, violent contact against an opponent with no play on the ball
Technical Foul - Foul called for unsportsmanlike non-contact behavior, penalized with 1 free throw
Clear Path Foul - Foul from behind on a fast break with no defender between fouled player and the basket
Player Control Foul - Offensive foul caused by the offensive player's own momentum or movement

A regular field goal made inside the 3-point line is worth 2 points
A field goal made from behind the 3-point line is worth 3 points
A free throw is worth 1 point
A player is awarded free throws if fouled in the act of shooting inside the 3-point line (2 or 3 free throws depending on where the shot was taken) or when a technical foul is called (1 free throw)
A player who is fouled in the act of shooting a 3-pointer is awarded 3 free throws
A basket made in the opponents' basket counts for the opponents' score

Center: Generally the tallest, they are usually positioned near the basket. Most teams play with 1 center (if you play with 0 centers, teams usually play with 3 guards)
Forward: May be called upon to play under the hoop, they may also be required to operate in the wings and corner areas. Most teams play with 2 forwards (power forward and small forward)
Guard: Best dribblers, passers and shooters (generally). Most teams play with 2 guards (point guard (brings the ball up the court) and shooting guard), however some times play with up to 4 guards.

Games are divided into halves at all levels.
In college, each half is twenty minutes long.
In high school the halves are divided into eight minute quarters (in nearly all states). In the NBA, quarters are twelve minutes long.
There’s a gap between the halves in all games.
If the score is tied at the end of regulation, then overtime periods of various lengths are played until a winner emerges.