Final answer:
Slapstick comedy, exemplified by exaggerated movements and harmless pretend violence, is the type of repeated gag in a play that creates cumulative comic effect.
Step-by-step explanation:
The type of "joke" or "gag" that recurs in a play for cumulative comic effect is known as slapstick comedy. This style of comedy can be traced back to the Commedia dell'Arte, where the slapstick, a paddle used to simulate physical comedy, originated. The comedic value in slapstick arises from the exaggerated movements and the pretense of violence that is not truly harmful. Notable contemporary examples of farcical slapstick comedy include Michael Frayn's 'Noises Off!' and Alan Ayckbourn's 'Bedroom Farce'.