The queens find themselves battling for laughs while impersonating their favorite celebrities on 'RuPaul's Gaff-In' with Vicki Lawrence's 'Mama', who is joined on the judge's panel by actress Busy Phillips.

The sixth week of performances features the celebrities dancing to country songs. Also: a group freestyle dance, accompanied by a song medley by Big and Rich and Cowboy Troy; and a performance by Little Big Town.

The knockout round begins. Here, the coaches pit two of their own team members against one another.

Benson wants to prove that he performed a famous drum solo.

Tony samples the flavors of the Dominican Republic. Included: a meal of empanadas and nearly frozen beer, followed by fried salami with tostones. Also: a helicopter ride to Samaná Peninsula for lunch.

XIII crashes an ultra-exclusive birthday party to find the final letter. The host of the party, and the owner of the letter, is a Russian Oligarch with a penchant for collecting expensive items such as rare weapons and beautiful women, and using the former on the latter. Part of his collection includes one of the Tesla letters, and XIII finds he isn't the only person who's come looking for it.

While investigating a shocking ritualistic murder, Beckett and her team uncover surprising evidence linking Castle to the killing. As the evidence against him mounts, loyalties are tested, and when surprising revelations come to light, Beckett begins to wonder how well she really knows her new lover and partner of four years.

XIII, Betty and Mozambique rush to free Vargas before he's deported to Guantanamo, as they believe he must have information about the letters. Synequanon's tests of their newest technology have unforeseen, cataclysmic results.

Connor Temple travels to Vancouver, to help with the set up of the new Anomaly research team in their base, the TANK.

In order to save Nora from her injury, Miles leads the gang on a detour to visit an old acquaintance of his for medical support, but they quickly find themselves in unfriendly territory. Aaron recalls his meek history as he looks back at his pre/post-blackout life, and Neville delivers Danny to Monroe.

Carly and her friends host a car wash at school.

Krysten Ritter, Blake Griffin, Bob Mould

Denzel Washington, Pauley Perrette, Paul Banks

Simon Cowell, Britney Spears, Billy Gardell, Two Door Cinema Club

Tom Hanks, Phil Handley

The arrival of new CT1 Lilah Birdwood causes ripples in the AAU playground as Michael and Serena do battle for her respect. But can Lilah prove herself worthy of their tussle or will she find herself on a plane back to Australia?

After some exotic lovebirds show up at the store as the new attraction to be sold, an overexcited Pauline offers to man the counter in an effort to impress Sam. After an expensive bird flies away, Pauline becomes panic-stricken. With Dudley's words ringing in his ears, Moray commits to a life-changing decision but regrets it straight away. Jonas resorts to blackmail to ensure his secret dealings remain hidden.

Despite the warnings of an experienced Miss Audrey, Denise is unable to keep her true feelings from Moray any longer... But will her actions cause her to leave The Paradise for good?

Rachel and Cuckoo learn that their nude Thai wedding ceremony on the beach wasn't as legitimate as they believed. This comes as welcome news to Lorna, who is pleased she's going to be witnessing her daughter's marriage. Ken sees this as an opportunity he's been looking for for ages which is a final chance to get rid of his son-in-law, once and for all.

It's Easter and JP invites the gang to stay at his country house, but things are not as idyllic as it seems. Josie has decided to mark ex-fiancé Dave's new wedding day in her own unique way. Howard and Sabine find themselves home alone and she makes him an offer he can't refuse.