When Zack is helping Miri rinse her hair, the shower curtain breaking, and Miri falling, was a complete accident.
In one sex scene, Lester (Jason Mewes) flips his tie around so it's hanging down his back. This was done because Jason has writer and director Kevin Smith's daughter's name (Harley Quinn Smith) tattooed down his back, and used the tie to hide the tattoo.
A portion of the plot is based on Kevin Smith's own experience in making Clerks (1994): a very low budget, working only with friends (including Jeff Anderson (Deacon) and Jason Mewes (Lester)), using a hockey stick as a boom microphone pole, and shooting the movie at his place of employment (the Quick Stop and RST Video in Clerks (1994), and the Bean 'N' Gone coffee shop in this film). Like Zack, Smith had to shoot at night after his work day was over, because the store had to stay open for business during the day. Lastly, Delaney (Craig Robinson) later uses money from his disability suit to finance movies; Smith partially financed Clerks (1994) with money from an insurance settlement over his car that had been destroyed in a flood.
Kevin Smith wrote the role of Zack with Seth Rogen in mind. In fact, Smith has stated that if Rogen turned down the role, the film would not have been made.
Zack (Seth Rogen) mentions making a porn spoof of Star Trek. Co-star Katie Morgan actually starred in a porn spoof of Star Trek called Sex Trek: Where No Man Has Cum B4 (2007).
Kevin Smith: [casting friends in his movies] long-time friends/collaborators Jeff Anderson and Jason Mewes play Deacon and Lester respectively.
Kevin Smith: [Star Wars] The porno the gang tries to produce is called "Star Whores", a spoof of Star Wars: Episode IV - A New Hope (1977).