Flight of the Conchords / Photo by Amelia Handscomb

Jemaine Clement and Bret McKenzie, the clever New Zealanders known as Flight of the Conchords, were owning a rambunctious crowd at NYC's Town Hall, running through a cheeky version of their song "Robots," in which the duo sing from the perspective of two robots who've recently eliminated the human race by using "poisonous gases" to "poison their asses." As the song concluded and the audience (which included Tim Robbins, Susan Sarandon, and members of My Morning Jacket) roared in approval, Clement noticed a bit of movement to his right: A few fans in the front row placed four or five wind-up robot toys on the edge of the stage which were duly marching around in all of their wind-up glory. Clement seemed pleased and said as much, collecting the toys and placing them alongside his stool onstage.

But then it got a bit ridiculous. Granted, this is a band that sings about racist dragons, rapping hippos, and David Bowie in Labyrinth (and whose album debuted last week at No. 3 on the Billboard charts). But a cavalcade of gifts continued to appear onstage: jellybeans (a reference to "Albi the Racist Dragon," whose tears turn into jellybeans), an eyepatch (culled from the lyrics of their ode to David Bowie), forks and knives (for the man in "Think About It" who is stabbed with forks and knives), and a curry-stained T-shirt (from "Business Time," Jemaine's ode to boring couples sex). The band's reaction went from chuffed ("It's a bit Rocky Horror [Picture] Show," quipped Jemaine at one point) to really freaked out.

And that prompts the question: Is there a point when this stuff goes a bit too far? Off the top of my head, I'm remembering Barenaked Ladies fans in the '90s who showered the band with Kraft Dinner (that's macaroni and cheese, for non-Canadians) during their song "If I Had a Million Dollars." Some other examples from our staff: Fans of the Alarm tossing cards into the air during one of their songs, Insane Clown Posse's obsession with Faygo soda, Morrissey's fans throwing flowers.

But where does the line get drawn? And what are some of the worst transgressions in the band-to-fan relationship? Post your comments.

Now Watch This: Flight of the Conchords, "Business Time"