Hoping to get Bobby to stop cracking jokes in school, Hank enrolls Bobby in a clown class at the local community college. The pretentious instructor teaches Bobby classical comedic theory and sucks all the fun out of him.

Woody is out to nab a cop killer whose crime leaves two teenage children fatherless, but when evidence inexplicably turns up at the scene he is suspected of planting it. Jordan and department psychologist Detective Tallulah Simmons team up, they must work together to clear Woody's name. Meanwhile, Nigel is intrigued with a woman's story about alien abduction and is determined to help her husband receive his dying wish.

Lynette tries to put a daycare center in Parcher & Murphy by recruiting employees' children to get the program started. Gabrielle and Sister Mary Bernard (guest star Melinda Page Hamilton) face off over Carlos mission of mercy to Africa. Bree brings Andrew home and tells him about the revelation of George poisoning his father Rex and killing him. Lastly, Susan confronts her biological father's wife after she thinks they are having an affair.

Cristina Yang has little sympathy for Constance Ferguson (special guest star Rosanna Arquette), a prison inmate who jeopardizes her health just to get out of solitary confinement. Meanwhile the interns all keep careful watch on the family of premature quintuplets with a variety of serious health challenges, Izzie's anger at Alex reaches boiling point, and Dr. Addison Shepherd decides to teach Izzie a very painful lesson.

After Aidan Grant, an employee for a local computer company, is found dead, Goren and Eames investigate, initially believing Grant was murdered because of a business deal gone wrong involving biometrics, lip-reading, the company Ubicool, and the military. Their investigation leads them to a young man who worked in the office opposite Ubicool. Goren soon realizes Robbie isn't fully in control of his actions and suspects his therapist of wrongdoing.

A federal agent goes undercover in Los Angeles to try and infiltrate a group of Islamic terrorists. Darwyn al-hakim finds an Islamic extremist guy named Farik. Farik asks him the join Sleeper Cell's plan to attack Los Angeles.

After the boost from the debate, Santos runs into trouble when he visits a Los Angeles community where a young African-American boy was shot and killed by a Latino police officer. Meanwhile, Ellie continues to plan her wedding, and C.J. deals with a crisis between China and Kazakhstan.

Larry finally learns the truth regarding his possible adoption, and makes his final decision about a kidney donation for Richard Lewis.

Female psychic Alex Sinclair visits Johnny during Christmas and the two team up to solve the mystery behind a lost Santa. However, Alex and Johnny have different visions of the Santa's life, making them wonder who this man really is. As their search progresses, they become involved with three street kids who come to Johnny's for the best Christmas in a long time.

Tom Dubois is accused of being an elusive killer so Huey must find the real killer, before a repeat of what happened to Tom in the past reoccurs.

Tiff Needell takes the Porsche Cayman for a spin on the A537, which has gained a reputation for being the most dangerous road in Britain. Tom Ford puts the fastest diesel cars to the test to see how they compare with equivalent petrol-powered vehicles, and Jon Bentley reports on the latest form of car crime - number plate theft.

Attention deficit hyperactivity disorder (ADHD) is one of the most feared and misunderstood of all medical conditions. Despite over 200 scientific papers being published on this neurological condition every year, it remains stigmatized and controversial. Some doctors don't even believe it exists. Yet it is estimated that as many as 3-5% of the childhood population, and over one million adults in the UK are affected by ADHD. These people are often described as stupid, lazy, disorganized, wild, out of control or woozy on drugs. But the reality is altogether more complex, and deeply moving.

Veteran DJ Tony Blackburn, folk singer Kathryn Williams, Radio 1's Nihal Arthanayake and comedian Adam Hills join regulars Mark Lamarr, Bill Bailey and Phill Jupitus on the comedy music quiz.