momlogic's Vivian: The remaining five "Idols" took on the work of Ol' Blue Eyes Frank Sinatra last night, with Harry Connick, Jr. as very involved mentor. However, Sinatra's work proved to be quite the challenge for some unsuspecting contestants.

Connick -- who described the iconic Sinatra's legacy as "great, great songs that can be interpreted in a myriad of ways" -- went way beyond the call of his mentoring duty, working hard on the arrangements and orchestrations of each contestant's song and doling out the requisite constructive criticism. "I should be out laying by the pool," he joked. "You think Shania Twain was up in here doing this?"

Frank's daughters, Nancy and Tina, were in the audience to present a gift that visibly touched Simon: a monogrammed hanky with Sinatra's initials.

Back to the nitty grit: Aaron hit the stage first, crooning "Fly Me to the Moon." His voice seemed a little thin at first, but he certainly looked his dapper best -- and received mild, positive reviews. Randy said he did "a really good job." Kara thought he was good but not as strong as last week, because he lacked charisma. Simon sided with Kara, saying, "Frank had a swagger. If he was a lion, you were a mouse. But you do try hard, and I'm going to give you that."

Casey then took on "Blue Skies," his hair slicked back in his best Mr. Sensitive Ponytail-Man look, but seemed visibly uncomfortable without his guitar strapped to his chest. Randy called it his worst performance. Kara said he "sounded like a lamb" and "needed to work on his vibrato." Yikes. Not good.

"MamaSox" Crystal did a tepid rendition of "Summer Wind" -- which also met with tepid reviews. She certainly looked lovely in a black strapless lace gown that showed off her full back tat, her hair swept in a glam updo. The band overpowered her until the bridge, when she started to throw down a few of her more expressive notes. Randy called it "one of her more subdued performances" and said "it was a little sleepy" for him. Ellen said that at first, it felt like Crystal was swallowing every word, and that she wanted her to loosen up a little more. Kara said Crystal was out of her element, but she "kind of liked it." Simon said frankly, "I love the song ... I don't know if I would have chosen it for you, though, because it felt a little bit indulgent. The first half was too jazzy for me, too small-nightclub. The second half obviously got a lot better. But I'm not going to lie and say that this is one of your strongest performances .... You've had two OK weeks. I think if you survive next week ... now it's about being in it to win it. It's about using this opportunity to nail it week after week after week. I expect better."

"I always try to do what I feel is best for the song," Crystal countered. "To me, it's a sweet love story, and you wouldn't sing it really big like that. If you're singing softly to your lover, you would sing it sweetly. And the song gets bigger as it goes on. I just don't feel like I should just sing really big notes because I'm on 'American Idol.' It should be about the music."

Simon replied, "I was just saying that, for you as an artist, you have one opportunity each week to absolutely present you in the best possible way. And I'm giving you this advice to help you, honestly."

So we'll have to see what happens there!

Meanwhile, Big Mike WAS in his element. His version of "The Way You Look Tonight" was flawless, emotional R&B, and the audience responded in kind. Randy called it an "unbelievable arrangement, unbelievable vocal," and said, "Mike is in it to win it -- this is what I'm saying!" Ellen said that out of everyone, he seemed to have the most comfort on stage and was able to "move easier than everybody else." Kara said that he took us on a journey and lost himself in the song. Simon said, "The first three performances have been OK, but with you ... you put it back in the game." Eyes on Mike!

Finally, affable Lee took on "That's Life." He sounded fantastic, and he was far more confident than usual. Randy admired how he "stayed his rocker self," Ellen said, "If this was the last night of performances, you would've just won this whole thing." Kara said she thought he could win this thing, and Simon called Lee's song "by far the best performance of the night so far."

So: The night's shining stars were Lee and Mike, MamaSox was fair to middling and Casey seems like he's on the chopping block. Who'll stay? Who'll go?

What do you guys think?