Inglourious Basterds (2009)
The Cameo: Mike Myers makes a wholly unexpected appearance as a plummy English military man.
Why It's Bad: Is it just us, or did Mike Myers sporting prosthetics and a British accent grow a bit tired some time ago?
Still, it could have been a lot worse - he could have been in his Fat Bastard suit.
Scary Movie 3 (2003)
The Cameo: Simon Cowell drops in to a half-baked 8 Mile sketch to pour scorn upon a pair of battling MCs.
Why It's Bad: Stilted doesn't even begin to cover it. "I don't know what I'm doing here," says Simon.
Neither do we.
The Cameo: M Night Shyamalan's obligatory cameo role, in which he plays a reckless driver responsible for killing Mel Gibson's wife.
Why It's Bad: A convincing actor, Night most certainly isn't. Clunkiest moment? "I'm truly sorry for what I've done to you and yours." You and yours? Urgh.
The Three Stooges (2012)
The Cameo: An extended cameo from the cast of Jersey Shore which goes on far, far too long.
Why It's Bad: Even a brief glimpse of the perma-tanned meatheads would be aggravating, but a series of scenes in which they drone out their lines like lobotomy patients really is beyond the pale.
Teenage Mutant Ninja Turtles 2: The Secret Of The Ooze (1991)
The Cameo: Bleached-blonde nineties no-mark Vanilla Ice drops in for a truly skin-crawling song and dance routine.
Why It's Bad: "Have you ever seen a turtle get down?"
Enough said, Ice.
Ocean's Twelve (2004)
The Cameo: Bruce Willis appears as himself in this painfully meta sequence involving Julia Roberts and a case of mistaken identity.
Why It's Bad: There's nothing wrong with Willis's performance per se, the problem is that the whole scene is so insufferably pleased with itself.
Keith Lemon: The Movie (2012)
The Cameo: Just when you thought this solid-gold stinker couldn't sink any lower, along comes Chris Moyles to duly take things down a notch.
Why It's Bad: At least Lemon's obnoxious, abrasive light-entertainment host is a character...
What To Expect When You're Expecting (2012)
The Cameo: Cheryl Cole makes an attempt at boosting her US profile by appearing here as a talent show judge.
Why It's Bad: Totally unconvincing in a role she's done for real on The X-Factor , Cheryl's publicity stunt was another Stateside washout.
Gremlins 2: The New Batch (1990)
The Cameo: Hulk Hogan gets pissed at a group of gremlins in the cinema, complete with a line of dialogue delivered straight to camera.
Why It's Bad: The use of the word "gremsters" alone is probably enough to warrant its inclusion.
Basic Instinct 2 (2006)
The Cameo: Stan Collymore (yes, that Stan Collymore) appears as Sharon Stone's first victim in this ludicrously OTT sequel.
Why It's Bad: No matter how sultry Stone's purring might be, there's no getting away from the fact that she's aiming it at Stan Collymore!