BASEketball is a 1998 David Zucker comedy feature film starring Trey Parker and Matt Stone along with Dian Bachar, Robert Vaughn, Yasmine Bleeth, and Jenny McCarthy. The movie follows the history of the sport (created by Zucker years earlier) of the same name, from its invention by the lead characters as a game they could win against more athletic types, to its development as a nationwide league sport and a target of corporate sponsorship. A sequel has been brought up, but no plans have been made as of yet. It's highly doubtful that David Zucker would return to this franchise, as he has other projects at the moment.

The film starts with the film's two protagonists — Joe "Coop" Cooper and Doug Remer — arriving uninvited at a party hosted by Brittany Kaiser, a high school classmate of theirs. During the party Coop and Remer find themselves outside on a driveway basketball court after they find their classmates have grown-up and moved on with their lives. There, they are challenged by a couple other party goers to a game for $50. Instead of playing that "pussy-ass 2-on-2 they play in the suburbs," they play a new game they picked up "in the hood." Clearly making this new game up as they go, Coop originally proposed Horse but changes it to basketball with baseball rules:

A single is at the free-throw line
A double is at the top of the key
A triple is from behind the key
A homerun is further back ("behind the meatballs" in the driveway)
You can't shoot from the same place twice
If you miss you get an out
During the challenger's first throw, Coop "psyches" him out to make him miss — a rule not explained previously. A "psyche out" can be anything said or done that makes the offense lose their concentration and miss their shot, such as Remer telling one of the other players he "fucked their sister". Physical contact with the shooter is assumed to be disallowed, though this was never explained in the rules. However, throughout the course of the film, defenders usually keep a few feet of distance between themselves and the shooters. However, on one occasion Remer fails to psyche out an opponent and resorts to beating his opponent to the ground with a board of wood. Though officals attempt to restrain him, he is not disqualified (nor is Coop, who also kicks the opponent while he is down)

After Coop and Remer win the game — perhaps because they were the ones who made up the rules as the game progressed — they realize they need to "stop playing games" so they can get jobs then they can get Dockers then they can get chicks. They proceed to play "baseketball" in their own driveway which gathers a large crowd. During this time their friend Kenny Scolari (cruelly nicknamed "Squeak", though he soon begins to refer to himself only by this name) joins the team.

Other rules revealed during the rest of the film:

A tip-in by the defense is a double play
A failed tip-in by the defense can be attempted by another defense player for the double play
A failed second defense tip-in can be attempted by an offensive player (a "conversion") and if they make it then the original shot is good
If the offensive player misses then another offensive player can try for the conversion as well
A "bunt" can be made from the orange circles. Although a bunt will not allow players on base it is a place you can shoot and not use one of the other nine areas to shoot from
A homerun can be attempted indefinitely, and, like bunts, is not subject to the "you can't shoot from the same place twice" rule.
Gay jokes are not allowed.

Six months after creation of the game, Ted Denslow shows up to propose creation of the National Baseketball League (NBL). Five years after creation of the game, the NBL is in full swing with stadiums, teams, fans, and a major championship (the Denslow Cup) with Bob Costas and Al Michaels as game announcers.

During the championship, Denslow chokes on a hot dog and dies. After the game, Jenna Reed introduces herself and a van full of kids to Coop and Remer as they leave the stadium to ask for autographs. The Will reading of Denslow reveals that Coop becomes owner of the Milwaukee Beers if he wins the next Denslow Cup, otherwise ownership goes to Yvette Denslow.

At the will reading it is revealed by Baxter Cain that Denslow created league rules that prohibit player transfers; teams moving to other cities; and corporate sponsorships. (The film's monologue reveals that all professional sports were reduced to players constantly changing teams; teams moving to cities constantly; and that cross-sport play was necessary in attempt to keep fans interested.) Changing of league rules requires unanimous consent by all team owners; Denslow was the only owner to resist changes that would reduce BASEketball to that of other sports. Cain then plots with Yvette to ensure that the Beers lose the next Denslow cup so that Yvette gains ownership and unanimous agreement can be attained to change the rules. He initially tries to talk with Coop to get him to agree to the changes, but Coop refuses to accept any of the rule changes.

Into the next season, Coop and Remer get involved with the Dream Come True Foundation where they meet Joey Thomas who needs a liver transplant. (Their involvement is probably due more to who the director is — Jenna Reed — instead of helping terminally ill kids have their dream come true.) Joey reveals that his dream is to hang out with the Beers. While hanging out, Coop promises Joey to make three homeruns at the next game.

Cain then tries to talk with Remer whom then goes to the Beers behind Coop's back when he realizes Coop said no to Cain without talking to the team. After Remer confronts Coop, Coop agrees to split ownership with Remer and the team. The team continues, however, to agree that the rules shouldn't be changed.

Cain then gets the funding cut for the Dream Come True Foundation, which leads to Remer — now part owner — to agree with Cain that the Beers needs to start a clothing line (BEERSWEAR) of which the profits will go to the foundation. This income is clearly not all going to the foundation as Remer starts wearing gold jewelry and signing movie contracts. Cain's plan all-along was to have the clothing line created in a sweatshop in Calcutta in order to get pictures to blackmail Coop and Remer to lose the Denslow cup.

Coop attempts to remedy the situation by flying to Calcutta. He then hires adult workers and gives them medical care, decent wages, and in-house child-care, and still manages to fly back in time to play in the Denslow Cup.

The Beers start with an abysmal performance, failing to make one hit in six innings. Due to Coop's flight to Calcutta, he had no time to practice, and spent the majority of the game "jetlagged and shitting curry." Remer, annoyed by the team's strong loyalty to Coop, put very little effort into the game, even filing his nails on defense, instead of attempting a psyche-out.

At the seventh-inning stretch, the Beers are down 16-0. Thanks to a tirade by Squeak — sick of Coop & Remer fighting — during the seventh-inning stretch show, Coop and Remer become friends again and they finally get back into the game and start scoring.

In the top-half of the 9th inning, Coop uses a Cartman voice to psyche the offense out. In the bottom-half, Remer is on second and Coop is up when his custom-made baseketball (La-Z-Boy) pops. Joey brings his custom-made baseketball for Coop to use (Barcalounger). Coop misses but successfully completes the conversion for the win and the Denslow Cup.

Special game nights:
Baseball games have been known to hand out free stuff to the first X number of people to show up. Baseketball continues this but hands out absurd stuff:

Milwaukee Beers vs. Dallas Felons — Dozen egg night
Milwaukee Beers vs. Miami Dealers — Free-range chicken night
Milwaukee Beers vs. Roswell Aliens — Anal probe night

All of the teams represent stereotypes and include references to their respective areas:

Milwaukee Beers
Reference to the numerous local beer breweries and the Milwaukee Brewers; the fans wear beer mug "foam heads" and perform "the chug" (similar to the Atlanta Braves "tomahawk chop"). Their mascot is a walking keg of beer (who can use his "tap" to urinate).
Miami Dealers
The players appear to be Cuban drug dealers. Note the chainsaw wielding man on the back of their jersey reminiscent of Scarface.
New Jersey Informants
The players are Italian-American stereotypes (one of their failed psych-outs was "Your mother's a terrible cook"); the cheerleaders also perform some Italian hand gestures.
San Francisco Ferries
The players wear white and pastel pink uniforms, and have the only all-male cheerleader squad. Of course, "Ferries" is meant to be a play on "fairies," an impolite term used to mean "homosexuals".
Roswell Aliens
Reference to the location where a UFO supposedly crashed and the surrounding conspiracies; the team has an alien mascot and an "Anal Probe Night" promotion.
L.A. Riots
Reference to the 1992 Los Angeles/Rodney King riots (and possibly Watts riots); the players appear to be angry Latinos.
Dallas Felons
Huge muscle types who are probably ex-convicts (a reference to the NFL's Dallas Cowboys, a team on which numerous players had legal problems in the mid-1990s).
San Antonio Defenders
Rednecks who chant slogans like "1,2,3, FUCK THE MEXICANS!" Their home field includes a giant recreation of the Alamo Mission.
Detroit Lemons
Reference to the home of American auto makers that supposedly produce inferior and defective vehicles (to which "lemon" is a reference)
When the league began to spin out of control, it was supposedly innundated with expansion teams. During the scene describing the extremely complex playoff system, references were made to teams in Boston, Atlanta, Indianapolis, Charlotte, Oakland, Toronto, Tampa Bay, Buffalo, Baltimore, Pittsburgh, and Denver. No nicknames or mascots were given for these.