Today on TV

NFL (6:30 p.m., ESPN): Broncos at Chargers.

How I Met Your Mother (7 p.m., Ch. 2): Barney urges Robin to become an American citizen.

Dancing With the Stars (7 p.m., Ch. 4): The competition continues.

Heroes (7 p.m., Ch. 5): Sylar tries to find out his true identity.

House (7 p.m., Ch. 13): A police detective who's about to turn 40 is worried — his father, grandfather and great-grandfather all died of sudden heart failure at age 40.

Accidentally on Purpose (7:30 p.m., Ch. 2): Billie and Zack have their first big argument.

Two and a Half Men (8 p.m., Ch. 2): Jake refuses to stay with Charlie and Alan after they embarrass him in public.

Trauma (8 p.m., Ch. 5): There's an explosion at a restaurant.

Lie to Me (8 p.m., Ch. 13): A man accused of killing his wife is determined to prove he's innocent.

Gossip Girl (8 p.m., Ch. 30): Vanessa and Blair compete; Dan brings Olivia home to meet the family.

Bud Greenspan Presents: 2008 Beijing Summer Olympics (8 p.m., Showtime): Greenspan's take on the Games is always great viewing.

The Big Bang Theory (8:30 p.m., Ch. 2): Sheldon (Jim Parsons) seeks revenge on his nemesis, Wil Wheaton of "Star Trek: The Next Generation." (Just the description of this episode makes me laugh out loud.)

CSI: Miami (9 p.m., Ch. 2): Alexx Woods and Eric Delko return to help the CSIs stop a deadly outbreak.

Castle (9:02 p.m., Ch. 4): Castle is offered a big opportunity — but it would mean the end of his relationship with Beckett.

Lincoln Heights (9 p.m., ABC Family): Lizzie and Andrew get closer.

Women's college volleyball (9 p.m., ESPNU): Idaho at Utah State

Greek (10 p.m., ABC Family): Greek presidents struggle and bad decisions are made.