What to Watch: Monday, January 18

Which How I Met Your Mother star gets to lock lips with guest star Amanda Peet? Relationships hit the rocks this week on The Secret Life, and Gretchen's BFF Claire gets a surprise visit from someone from her past on Heroes. Monday, January 18

Amanda Peet guest stars on How I Met Your Mother.

8:00 pm How I Met Your Mother, CBS (30 min) NEWMarshall’s hot co-worker (guest star Amanda Peet) kisses him, much to Lily’s disbelief, while Robin learns that a drinking game was made up about her. Also starring out actor Neil Patrick Harris. 8:00 pm The Secret Life of the American Teenager, ABC Family (1 hr) NEW Tensions flare when Ricky and Adrian argue over money struggles, and drama ensues with Amy and Ben as they try to salvage their relationship. Even Tom and Tammy can’t get along in this episode. Let’s hope that Ashley’s favorite gay, Griffin (Brando Eaton), will help everyone kiss and make up. 9:00 pm Heroes, NBC (1 hr) NEW Claire may need the advice of her lesbian bestie, Gretchen, after Sylar pays her a visit, while Samuel tries his hardest to show off to Vanessa. Hiro faces some serious retribution for abusing his powers.