* The Secret Life of The American Teenager (8 pm/ET ABC Family)
Ever wonder how shy Amy hooked up with playboy Ricky last summer at band camp? As Amy goes into labor, she flashes back to that fateful day she first met Ricky nine months ago and recalls how the charming drummer pursued her and gave her his undivided attention. Meanwhile, Tom does his best to get his sister and Jack back together, and Adrian can't deny that she still has feelings for Ricky.
* The Big Bang Theory (8 pm/ET CBS)
Penny starts her own hair-product business from home, but she soon realizes that mixing business and friendship is about as successful a combination as the mullet and frequent dating. A caffeine-addled Sheldon gets involved, and Penny can't seem to get him out of her hair...or prevent him from ruining her business.
* Kyle XY (9 pm/ET ABC Family)
After three seasons, this teen drama meets sci-fi show comes to a close. Ever since he came out of the pod, the boy without a belly button has been searching for answers from the companies involved in creating him. Tonight, Kyle learns some of those answers when he gets Cassidy to reveal Latnok's true plans, which involve mass-producing "super children" like himself and Jessi. Kyle attempts to stop this from happening, and he leans on those closest to him to help in this endeavor.
* 24 (9 pm/ET Fox)
Jack's on the lam after being framed for killing a witness to the conspiracy when he comes face-to-face with Sen. Blaine Mayer, the man who's been trying to bring him down. Meanwhile, Jon Voight, who this season took on the role of Jonas Hodges, yet another in the pantheon of deliciously wicked villains the series has had over the years, puts an evil plan in motion.
Poor Whit! As the first season of The Hills spin-off wraps up, the breakup with Jay is making her wonder if moving to New York was the right choice after all. And while Lauren Conrad could always rely on Whitney to be the caring coworker/sidekick she needed on The Hills, the villainous Olivia has been anything but. So what's a girl to do? Well, phoning up her old pal LC is a good place to start. Will the reality TV veteran be able to convince the show's star to stay in the Big Apple? It's pretty likely, considering the series has already been renewed for a second season.