Britney Spears - "Glee"
"Glee's" first Britney tribute was its most-watched episode, but the cameos by Spears herself left a lot to be desired. In Rachel's "…Baby One More Time" sequence, the pop star was barely noticeable, on screen for only a second to flip her hair as the hot substitute teacher. Later on, she's one of the McKinley High School cheerleaders, and in the third part of her cameo, Britney appears in "Me Against the Music," telling the other Brittany that she smells good. It's supposed to be a fantasy, but it's really just awkward, and definitely not the most effective use of Spears' talents.
Will.i.am - "Joan of Arcadi"
Will.i.am's name on "Joan of Arcadia" was "Three Card Monty Guy God," so that pretty much sums up how important his role was. In the over-acted 30-second cameo, the Black Eyed Peas frontman preaches to Joan about making her own choices and keeping her eyes open to the world around her. If you listen carefully, you can even hear a Will.i.am track playing quietly behind the dialogue.
Snoop Dogg - "90210"
As much as Snoop Dogg's cameo on season two of "Weeds" can go down as one of TV's best, his appearance on the third season of "90210" is one of the worst. Bragging about cars, complimenting Dixon's "'Rari" and driving through L.A. with a high schooler, playing his unreleased single -- without a joint in sight? We hardly believe that's what an afternoon with Snoop would look like.
Iggy Pop - "The Adventures of Pete & Pete"
Back in the early '90s, punk pioneer Iggy Pop appeared on a few episodes of Nickelodeon's cult classic series, "The Adventures of Pete & Pete." In the cheesy cameo, the veteran rocker played Michelle Trachtenberg's father, the aptly-named "Pop," who jumped on stage at the school dance to sing his daughter a song. Oddly enough, Iggy's cameo wasn't the only one in that episode of "Pete & Pete" -- the band that had been playing before he jumped on stage was led by a Luscious Jackson member.
Alice Cooper - "Monk"
It wasn't Alice Cooper's fault that his "Monk" cameo was one of the lamest moments on cable television. We personally blame the writers, and whoever booked the ill-fitting gig on the USA series. It didn't make sense within the episode -- yes, Monk was going crazy from the smell of garbage on the street of San Francisco, but that's no excuse -- and all the "School's Out" singer did was sit in a chair and snarl. Next time Cooper appears on a serial detective dramedy, we hope he's given a role with more grit. Or at least a few lines.