Walden plans a big surprise for Zoey's birthday.

Zoey and Walden break up, causing Walden to experience a breakdown.

Alan and Lyndsey decide to spice things up in the bedroom.

Walden starts to feel his age when a friend's daughter comes to town.

Despite Alan's warnings, Walden starts dating Rose.

Walden must choose between Zoey and Rose.

When Walden gets tired of the complications that come with a traditional relationship, he hires an actress to be his girlfriend; Jake plans a rendezvous with Missi (Miley Cyrus) at the beach house.

Alan feels reluctant to make a commitment to Lyndsey, but an unexpected source inspires him; Walden enjoys being the boy-toy of a wealthy older woman.

Alans famous ex-wife, Kandi, wants to reconcile; when Berta isn't interested in celebrating her birthday, Walden tries to make her day special.

Alan helps Walden create a new identity so he can avoid women who are only interested in his money.

Walden juggles his two identities; Alan ends up alone on Christmas.

Alan invests Walden's money in Kate's fashion line; leading a double life takes its toll on Walden.

Alan and Walden go to Kate's fashion show in New York so Walden can reveal the truth about his identity.

Alan is faced with relationship trouble when he does not give Lyndsey a key to the beach house; Walden, Alan, Herb and Billy commiserate about relationships.

When Jake brings his 36-year-old girlfriend home for a visit, Alan is concerned; Walden tries to hide something from Alan.

Depressed on Valentine's Day, Walden tries to talk Kate into giving him another chance; Alan's holiday plans go south.

When Walden runs into his ex and they start talking about getting back together, Alan worries that she is not good enough.

After a fight with Walden, Alan decides to move in with Herb.

Alan and Walden end up partying too hard as they try to cheer up Herb.

Walden and Alan are caught in the crossfire when Jake cheats on his girlfriend (Jaime Pressly) with her 18-year-old daughter.

Alan has a difficult time coping when Lyndsey breaks up with him.

With encouragement from Walden, Alan decides to update his look; Alan is faced with a moral dilemma when he attracts a married woman.

Walden dates an attractive 22-year-old (Hilary Duff), but ends up being more interested in her grandmother (Marilu Henner); Jake and Alan go on a trip.