American Idol (8pm, Fox) - It's time for the judges to lock them doors and turn them lights down low -- and finally unveil the Top 24 semifinalists, which will consist of 12 males and 12 females. Will Garner's country-crooning Scotty McCreery (left) be in that group?
Big Bang Theory (8pm, CBS) - Sheldon learns he's not the epicenter of the group and decides to find new friends.
Grey's Anatomy (9pm, ABC) - Meredith discovers that her fertility treatments are causing her to lose her visioni, and Mark tells Callie and Arizona that he plans to be an active dad when the baby comes.
Royal Pains (9pm, USA) - In the Season 2 finale, Hank tries to get to the root of what's ailing a patient he thinks has been misdiagnosed. Elsewhere, Divya and Raj take dance lessons for their upcoming wedding, but things don't go as planned.
Parks & Recreation (9:30pm, NBC) - Ron and Leslie head to Indianapolis, where they'll be recognized for their work on the upcoming Harvest Festival. Back in Pawnee, Tom hosts a launch party for a local cologne maker, and Andy and April find ways to have fun without spending money.
30 Rock (10pm, NBC) - Liz hires a new female writer after a blog declares "TGS" misogynistic. Meanwhile, Jack plots his takeover of Kabletown by zeroing in on his main competition -- the CEO's granddaughter.
Archer (10pm, FX) - When members of Woodhouse's WWI Royal Flying Corps squadron (the "Double Deuce") start dying mysteriously, he naturally suspects foul play. So does Archer, who' sin for some multitasking: tracking down the killer while babysitting his young son Seamus.
Perfect Couples (8:30pm, NBC) - I have decided this new sitcom about three messed up couples is unfairly maligned, so tonight I encourage everyone to give it a shot. It's not perfect (ha), but it has some solid crack-up moments. In this episode, Dave and Julia deal with jealousy after Dave meets a woman while hiking and Julia hits it off with a coworker. Not to be left out, Vance and Amy play games to make each other jealous. Also, Rex has trouble talking to Leigh about their financial troubles.
Vampire Diaries (8pm, CW) - Katherine's past is explored in 1490 Bulgaria, and Damon tries to uncover the real purpose of the mysterious moonstone.
housewarming party.
30 Rock (8:30pm, NBC) - Jack tries to save Liz and Carol's relationship, and Jenna and Kenneth turn to Kelsey Grammer (appearing as himself) for help.
30 Rock (8:30pm, NBC) - In this episode, performed live, Liz Lemon fumes during show night when the "TGS" gang all forget that it's her 40th birthday. Meanwhile, Tracy concludes that it's hilarious whenever an actor breaks character and laughs, so he does that all night long. And Jack has trouble in his efforts to stop drinking during Avery's pregnancy. The "30 Rock" cast will perform the show live for a second time tonight for the west coast audience.
Community (8pm, NBC) - In the Season 2 opener, the group reconvene to study for their anthropology class, which is taught by a kooky professor (Betty White, of course). Meanwhile, Senor Chang enrolls at Greendale in hopes of joining the study group.
I don't see how it's going to help him get his EGOT, but Tracy Morgan (aka Tracy Jordan from NBC's Emmy award-winning "30 Rock") is coming to Raleigh to do a four-day stand-up gig in September.
Bones (8pm, Fox) - In the fifth season finale, the death of a hoarder has the team sifting through the man's many possessions looking for clues. Angela gets a visit from her father, ZZ Top guitarist Billy F. Gibbons (left, as himself).