The Unpronounceable Alias
One of our heroes is traveling or acting under false pretenses, and is asked for their name when they'd really rather not give it. Unprepared for this, they quickly stammer something that's barely a word at all, let alone a name. If it's supposed to be a full name, it often ends in "the Third".
A few examples below, but you should read the entire page (good luck stopping after you get started -- I have lost entire afternoons to TV Tropes).
In Mr. Deeds Winona Ryder's character, an investigative reporter, makes up a false identity in order to investigate Longfellow Deeds. When Deeds asks where she's from, she hesitantly makes up the town of Winchestertonfieldville, Iowa. Unfortunately, the plan backfires when Deeds ends up taking her on a trip to her supposed childhood home in Winchestertonfieldville...
A Fish Called Wanda The rather dense Otto is attempting to explain to Archie Leach's wife just what the heck he's doing in her house. Part of his flimsy cover includes the alias Mr. Manfrenjensen...jen. When she picks apart his story, she idly repeats this pseudonym perfectly.
The Simpsons In the episode "The Last Temptation of Homer", Homer feebly suggests the alias "Joey Joe Joe Junior Shabadoo". Unimpressed, Moe says it's the stupidest name he's ever heard. As a patron gets up and exits the bar, weeping, Barney calls after him "Joey Joe Joe...!"
Technorati tags: TV Tropes, fake, names, aliases