Hot. Tranny. Mess. Project Runway wunderkind Christian Siriano makes his much-anticipated cameo on Ugly Betty this evening, along with P-Run judge (and recently fired Elle Magazine editrix) Mean-a Garcia. We wonder: Will it be fierce? Flawless? Fabulous? Some magical combination of the three? (ABC, 8 PM)

Tune into this week's episode of Step It Up & Dance for an inexplicable cameo by Seinfeld alum and KFC shiller Jason Alexander, perhaps the least athletic-looking actor since Jackie Gleason (Bravo, 10 PM).

Whether you feel like commiserating over a dumb-dumb boss or just think John Krasinski is a hot piece of arse, there's no shortage of reasons to watch this new episode of The Office, in which Steve Carrell's unwaveringly clueless Michael Scott makes another foiled attempt to win his co-workers' love. (NBC, 9 PM)

Prepare yourself for more pants-pooping suspense and all-around intense craziness on this week's episode of Lost. Does Jack have the Bubonic plague? Or just a bad case of the Clap? Is Alex really dead? Or were those blanks in the bad guy's gun? So many questions to answer. So little Xanax. (ABC, 10 PM)

At 30 Rock, Liz Lemon contends with an ex-boyfriend and Jack Donaghy continues his quest for supremacy at NBC. And as per usual, we expect an embarrassment of bons mots from Kenneth the Page and Tracy Jordan. Though we're still waiting for this season's equivalent of "Werewolf Bar Mitzvah." (NBC, 9:30 PM)

File under: Weirdest premise for a reality show. Yes, weirder than Farmer Wants a Wife (but with a much better name). On Celebracadabra, celebrity contestants pair off with professional magicians. This marks celeb contestant Carnie Wilson's 83rd foray into the world of reality programming. Oh, and for you film buffs: Illusionist David Friedman appeared with his cuckoo-banana family in the 2003 child-porn documentary Capturing the Friedmans. Creepy. (VH1, 11:05 PM)