One of the questions Artie suggests to ask when investigating artifact effects, "Do you smell fudge in places where there are no fudge?", becomes a bit of a running joke in the series. Midway through the first season, Myka uses the phrase "I smell fudge" to tell Pete that she's on the trail of an artifact; in the season two premiere, Artie identifies an invisible mine by smell, which Claudia immediately states is fudge.
There was considerable actor crossover between "Warehouse 13" and "Eureka'. Not only did Allison Scagliotti appear on Eureka as her Warehouse 13 'Claudia Donovan' character but Neil Grayston appeared on Warehouse 13 as his Eureka "Douglas Fargo' character. In addition Erica Cerra (Eureka's Jo Lupo), Joe Morton (Eureka's Henry Deacon) and Niall Matter (Eureka's Zane Donovan) appeared on Warehouse 13 as other characters. Cerra and Matter were husband and wife con artists and Morton was a prison preacher. Likewise Saul Rubinek (Warehouse 13's "Artie") appeared on "Eureka" as Dr. Carl Carlson.
Pete, Myka, and Steve discuss the artifact being "cursed" by an actor who Shakespeare didn't like, due largely to the fact that he improvised too much. The writers likely inserted this as an in-joke aimed at Eddie McLintock, who was notorious for forgetting his lines and improvising his way out of trouble on a regular basis.
Many of the aspects of the characters of Pete and Myka were influenced their actors, Eddie McClintock and Joanne Kelly respectively. For example, McClintock suggested Pete should be a former marine, and love comic books, and Kelly asked for Myka to love literature and be a book worm.
The trivia item below may give away important plot points.
The umbilicus that runs from the front door of the Warehouse to the main office is actually a hallway in a Toronto hospital. Allison Scagliotti mentions in the Season 1 commentary that the hospital that contains the umbilicus hallway is the same hospital where, many years previously, Saul Rubinek's father passed away. Years after his father's death, Saul Rubinek would return to the hospital to film the death scene of his character Artie Nielsen.