Katy Perry and Avril Lavigne know exactly what it's like to have a musical dream. Both were once teenage girls who had to scrape and paw their way to pop stardom, which is why the youngest "American Idol" guest judges to date were perfect for the Los Angeles round of auditions.

Despite being the entertainment capital of the world, the L.A. auditions on Tuesday night's (January 26) "Idol" provided very few fireworks -- except for the catty exchanges between Perry and fellow judge Kara DioGuardi, which were among the most entertaining moments on an otherwise lackluster evening.

One of the night's biggest standouts was 28-year-old Burbank, California, native Mary Powers, mother of an 8-year-old girl, who put a smile on Lavigne's face with an impassioned take on Pat Benatar's "Love Is a Battlefield."

Simon Cowell liked the vocals but called her black-on-black ensemble a clichéd attempt to dress like a rock star. "You do have a character to your voice and a cool tone. It's raspy and it is punk rock, so I think it's cool," Lavigne said of the female singer with the Adam Lambert hair and bondage pants.

Apparently, this year the [article id="1630558"]Lambert effect is all over the place[/article], from the many auditioners showing up with asymmetrical Adam hair, to the vocal inspiration of A.J. Mendoza, who sang Living Colour's "Cult of Personality." OK, the 20-year-old musical-theater performer didn't sing it so much as emote it like he'd "gone to the dentist 10 minutes ago," according to Cowell, who likened his vocals to anesthetized mush.

It wasn't all bad, though. Pastor and father of three Neil Ranger, 27 -- following in the footsteps of last year's [article id="1606966"]church-trained worship leaders Kris Allen and Danny Gokey[/article] -- impressed the judges with his original country/soul tune "Drive." Lavigne wondered whether his busy home life might make it hard to hit the road and said no, but the other three panelists gave him a shot at Hollywood.

With her devil-ear hoodie and armful of plastic bangles, Lavigne giggled like a schoolgirl and could hardly contain herself at the worst singers, giving [article id="1629668"]guest judge Mary J. Blige[/article] a run for her money in the trying-to-stifle-a-laugh department.

You couldn't really blame her, with the sweaty 168-IQ computer geeks with Prince Valiant hair and bedazzled vests who just wanted to exultate (whatever that is) but who mostly just made the panel uncomfortable by butchering Meat Loaf and refusing to leave the room. There were the metal screamers, lyric-fudgers and a flute-playing, sandwich-making, pacifist martial artist in search of the perfect note, whose journey will seemingly continue indefinitely.

On day two, Perry was up to bat in the city of show-biz dreamers that appeared to be producing very few potential stars.

She had no better luck, sitting through water-treatment workers/ glam-rock wannabes murdering Cheap Trick classics while doing Mick Jagger-style aerobics, and creepy, dead-eye guys who believe in magic but know nothing about song choice (i.e. Don't pick the Divinyls' "I Touch Myself" for an audition). "It takes a lot for me to feel dirty," the "I Kissed a Girl" singer told the latter, which tells you just how skeevy he was.

Another dad had what it took, though. Andrew Garcia, 23, whose parents were involved in Hispanic gangs in L.A., was in search of a better life for his son, and he may have found it in the "Idol" audition room. Singing a very soulful version of Maroon 5's "Sunday Morning," Garcia got the ultimate compliment from Cowell, who said he was "the only person who's walked through today who I genuinely believe is a good singer." Perry seconded that emotion, saying he gave her chills, and both DioGuardi and Randy Jackson gave him major props as well.

Personal assistant by day, minister by night Tasha Layton, 26, killed it with Joss Stone's "Baby, Baby, Baby," nailing the sweet-pop soul vocals and even evoking a bit of Stone's funky hippie vibe. "I love a good Southern belle," Perry purred, while Cowell predicted people were going to really like her.

And while the medical drama of previous audition episodes subsided for at least one night, the show-closer was 25-year-old Los Angeles shoe salesman Chris Golightly, who spent his childhood bouncing around between 25 foster families.

He channeled the pain of his lonely upbringing into a very solid take on Ben E. King's "Stand by Me," hitting some emotional, breathy runs and leading DioGuardi to say that he was one of her favorites and that "we may look back at this audition and go, 'Wow.' "

The latter's reaction to Golightly's story elicited a bit of a catfight with Perry, who appeared to clash with DioGuardi several times during the auditions and who disagreed with the notion that dramatic backstory could help him on the show. "This is not a Lifetime movie, sweetheart," Perry said, dissing the woman with whom she co-wrote Kelly Clarkson's "I Do Not Hook Up."

"He has an amazing story," DioGuardi countered.

"He has an amazing story, but you have to have talent," Perry said. "Everybody has amazing stories."

Cowell was not feeling it either, saying Golightly could have been in a boy band and gave an old-fashioned audition, though he put him through anyway with a "small y" yes.

In the end, 22 others from Los Angeles made it through to the Hollywood round. Wednesday night's show will head to Dallas with guest panelists [article id="1630472"]Joe Jonas[/article] and Neil Patrick Harris.

Get your "Idol" fix on MTV News' [article id="1486475"]"American Idol" page[/article], where you'll find all the latest news, interviews and opinions.