Perhaps the most surprising performance of Tuesday's American Idol was the down-to-earth appearance of Mariah Carey. With nary an ounce of diva or crazylady behavior in sight, nor an appearance by is-he-or-isn't-he paramour Nick Cannon, Mimi had lots of sweet smiles and compliments for the remaining seven contestants. And of course tremendous amounts of cleavage. Some things, thankfully, can always be relied on.

Host Ryan Seacrest opened the show with the question lingering on many people's minds: When most contestants are criticized for taking on a Mariah Carey song because of her inimitable voice, how would any of them do on a night dedicated exclusively to her songbook? Judge Randy Jackson said the answer was in not trying to sound like Mariah but in contestants being themselves. Some delivered in spades, and others stumbled embarrassingly.

Starting off the night and setting the bar high was David Archuleta, who downshifted the Mariah-Whitney Houston duet "When You Believe" into the feel-good ballad model that has become his signature. The judges all agreed the performance was impressive, and Archuleta should be safe and sound in the top six.

Carly Smithson,, who can seem to do no right in the judge's eyes, followed with a version of "Without You." The song sounded great to this viewer, but the judges called it "pitchy" and said she tends to overthink it all too much. Methinks they're a little hesitant to hand a record contract to a girl whose husband looks like he just stepped out of the jungles of Borneo. Just a theory.

Faring slightly better was Syesha Mercado, who's been criticized in the past for taking on Mariah songs too big for her voice—she played it smart and chose a song not many people know, "Vanishing." Simon Cowell summed it up with a compliment: "Technically very good, indeed." Brooke White tried her best to bring a singer/songwriter vibe to "Hero" by speeding it up and sitting at the piano. She lost her confidence in the middle of the song, though, and there was a collective gasp when a closeup caught her shaking. Not willing to criticize her, Paula offered a nonsensical evaluation: "Every ounce of you is totally authentic to who you are." Simon was a bit more direct, saying the performance was "a bit like ordering a hamburger and only getting the bun." Randy disagreed slightly, saying, "The meat was there, but the condiments were missing."

Strike three for the girls came with Kristy Lee Cook, who continued her mini-comeback with a relatively strong performance of "Be"—but she was quickly overshadowed by the other Cook, David, who turned the night on its head with a rock version of the pop staple, "Always Be My Baby." Delivering a truly unique and haunting version of the song, David drew a standing ovation from Randy Jackson for the first time of any contestant this season, along with the compliment that in his estimation, Cook's is ready to make an album. Cowell admitted it was "original, daring, and stood out by a mile." Jason Castro then took the stage and turned "I Don't Want to Cry" into a completely different tune—soulful, acoustic, and bongo-inflected.

As predicted by Cowell at the top of the night, Mariah's night was actually better-suited for the boys—in tonight's results show, expect the remaining ladies in the competition to comprise the bottom three.