The grueling singing semifinals come to an end as the final group of 10 singers perform for the judges in hopes of keeping their coveted spot on the show. After tonight, only the Top 20 semifinalists will remain in the competition. Next week, it will be up to America to decide who will make it to the Top 10 and who will be sent home. Find out if your favorite contestants make the cut.

After losing out in registration for "The History of Ice Cream", the study group begins their European History class with Professor Noel Cornwallis. To make matters worse, the group encounters the return of the arrogant German students from last season, which Jeff and Shirley faced over the foosball table. Meanwhile, much to Dean Pelton's dismay, Chang makes his return to campus.

Sarah and Tierra are among the rejected bachelorettes who confront each other and Sean. Also: Sean and Chris Harrison review the season and look ahead to the finale.

With a renewed determination to find Laila, Hank returns from India, searching for new clues while Laila, who is being held hostage by White Vincent, is tasked with repairing the next clock for him. Knowing she needs to help Hank find her, she starts leaving a trail of clues for him to follow. In another face-to-face showdown with White Vincent, Hank begins to realize there is more to this connection than meets the eye - or in this case White Vincent's eyes. Meanwhile, Hank's parents seem to be hiding a secret, and with help from the FBI, Hank, Arron and Rachel discover that a famous historical figure holds the key to unlocking the next clock.

Fashionable clothes for senior citizens are created by the contestants. Joan and Melissa Rivers are the guest judges.

Walt works a deal for an original Asteroids arcade cabinet, while Ming has a thing for his childhood G.I. Joes.

A fish kill of biblical proportions hits the swamp, causing the gators to stop biting lines, and forcing swampers to get inventive in their hunting strategies.

Charlie takes on Cee Lo Green as an anger therapy patient.

When unable to make a decision about who to nominate to the Supreme Court, President Dale Gilchrist decides to take a family trip to their ranch to clear his head. During their getaway, Skip finds himself moping over his failed relationship, while Becca contemplates major flaws in her own relationship. Meanwhile, Emily attempts to spend some quality time with Marigold and Xander, who both struggle with their loss of technology while at the ranch.

The laws of physics - as well as some broken glass - decide which nerd is safe from exile in this week's Nerd War, and it comes as a surprise to all. To determine the final four contestants, one last nerd-Off tests the nerds and the structural integrity of their engineering wonders.

Archer, Lana, and Cyril go undercover in celebrity chef Lance Casteau's hellish kitchen.

Comedian Nathan Fielder gives marketing advice to small businesses in this series, which begins with a campaign for a frozen-yogurt shop to offer an unconventional flavor; and a plan for speedier pizza delivery.

After missing out on a role because of his weight, Jim turns to his good friend Andy Dick for some career advice, acting lessons and physical training. Jim ends up ruining the trainer.

Rachel Maddow

Kunal Nayyar, Julian Newman, Eugene Mirman

Obama speechwriter Jon Favreau

Charlie Sheen, Phil Simms, Jose James

Steve Carell, Joey King, Shooter Jennings

David Duchovny, Ashley Madewke

Host Jimmy Carr and team captains Sean Lock and Jon Richardson are joined by celebrity guests as they thrash out the hot topics of the week by examining surveys, opinion polls and statistics; from the silly to the serious, from celebrity gossip to world politics.

Jonathan Ross joins Adam Hills, Josh Widdicombe and Alex Brooker as they provide their take on the topical moments of the past week.

Graham is joined on the show by James Franco, Mila Kunis, Jude Law, Judi Dench and Olly Murs.