David Caruso and Teri Polo, CSI: Miami David Caruso and Teri Polo, CSI: Miami

CSI: Miami
10 pm/ET CBS
Seven seasons...150 episodes...countless pairs of sunglasses removed. Yes, the sun-soaked series reaches an important milestone with tonight's intense hour. The 150th episode, titled "Gone Baby Gone," features guest star Teri Polo as a frantic mom whose baby is kidnapped and held for ransom. — Tim Holland

For full episodes of CSI: Miami, visit our Online Video Guide.

Dancing With the Stars
8 pm/ET ABC
Tonight it's the semifinals, which means the judging gets more critical and the dancing gets more intense. Brooke Burke, Warren Sapp, Lance Bass and Cody Linley (reunited with his original partner, Julianne Hough) battle it out for a spot in next week's finals. The mirror-ball trophy is within their reach, but a slip like sloppy footwork or bad posture could cost them dearly. Tune in to see who can handle the pressure and bring his or her A-game when it's needed. — Jennifer Sankowski

For clips of Dancing with the Stars, visit our Online Video Guide.

Heroes
9 pm/ET NBC
For those of you still stuck on the edge of your seat after last week's shocking ending, the wait is almost over. Hiro's fate — and the fate of his head squeezed between the crazy-scary Arthur Petrelli's hands — will be revealed. Also, in not-so-happy reunion news, Nathan finds out that his dad is alive, and Elle and Sylar have a run-in at Pinehurst. — Brie Hearn

For full episodes of Heroes, visit our Online Video Guide.

One Tree Hill
9 pm/ET CW
Chad Michael Murray's onscreen alter ego, Lucas Scott, is a successful novelist, and it turns out that Murray is a budding writer as well. He penned tonight's episode, which is anything but a typical hour of One Tree Hill drama. Instead, it's a dream sequence that pays homage to classic films of the 1940s, complete with costumes and settings from that era. Karen's Café transforms into a glamorous nightclub, and Lucas becomes a nightclub proprietor. — Jennifer Sankowski

For full episodes of One Tree Hill, visit our Online Video Guide.

The Big Bang Theory
8 pm/ET CBS
Sara Rue guest stars in an episode that creates a rivalry between two of the guys that isn't about video games or their work. Wolowitz, as we all know, would be happy to find any woman who would be interested in him — but he actually thinks he's found his true soul mate (Rue), that is, until the woman meets Leonard and falls for him! — Bill Ecklund

For full episodes of The Big Bang Theory, visit our Online Video Guide.