In florida its pretty common to see people playing 21 when you go to the court usually waiting for more people to show up or to warm-up.

it goes like this:
first one to reach 21 wins every time you score you either go to the free-throw line or the 3pt line each shot you make there counts as 1 until you miss.

you can also play with tips thats when the ball bounces off the rim you grab it in mid air and put it back in either with two hands or one.

Two hands= you going back down to 0 automatically
one hand= You being out.. of the game but someone can throw you back in once they score..

o and when you reach 20 and your shooting the free throw if you miss you go back down to 15.

__________________
Long live da king