Basketball: a practice that is growing in the sport, especially at the professional level
Soccer: called "diving," a long-accepted part of the sport
Boxing: done by only the dumbest and least successful boxers
Football: done by the dumbest and least successful football players; sometimes appears that certain offensive or defensive linemen are doing it, but this is only by accident due to lack of skill and strength (see: St. Louis Rams)
Baseball: a way to make catching a routine flyball seem exciting and acrobatic; brought into fashion by former Angels and Cardinals outfielder Jim Edmonds
Hockey: like in soccer, called "diving;" also called "drawing a penalty" if you like the player who dove
Marathon running: most likely a sign of exhaustion or a seizure
Fishing: something that dramatic fish do in their final moments, as they suffocate to death on a boat
Horse racing: term used to describe what a horse's broken leg does after it snaps in a race
Extreme sports: probably an annoying slang term for a trick that gets people "stoked"
Racing: not practiced, but is probably something that would lead to awesome, fiery crashes so they should totally do it
Women's sports: a term used to describe the breasts of competitors who don't wear sports bras
Spelling Bees: done by clever kids pretending they are passing out as a means to stall for more time
Mountain climbing: called "suicide"
Diving: called "diving"

