Joey shows his Ichiban commercial to Chandler in the Season 10, Episode 6, The One with Ross's Grant. Joey tries to act in a commercial that Chandler's ad agency is doing. He shows Chandler a video of his commercials, starting with the Ichiban, lipstick for men, commercial he did in Japan.
Chandler proposed to Monica in Episode 25, Season 6: "The One with the Proposal, Part 2"
Season 7, Episode 23, The One with Chandler and Monica's Wedding. Ross has the "older brother" chat with Chandler and threatens to beat him up if Chandler makes Monica unhappy.
The One With All The Rugby
The One With the Embryos
This was in season 8, episode 21, The One with the Cooking Class. Phoebe gives advice and preps Chandler for an interview.
Chandler proposed to Monica in Episode 25, Season 6: "The One with the Proposal, Part 2"
Season 7, Episode 23, The One with Chandler and Monica's Wedding. Ross has the "older brother" chat with Chandler and threatens to beat him up if Chandler makes Monica unhappy.
A hilarious one
The One With All The Rugby
The One With the Embryos
This was in season 8, episode 21, The One with the Cooking Class. Phoebe gives advice and preps Chandler for an interview.
Season 2 Episode 7 The One Where Ross Finds Out
Season 4 The one with the embrios
Yes he did. It was a funny episode.
Season 9, Episode 19, The One With Rachel's Dream
The episode is called The One with All the Thanksgivings from season 5.
There is one funny episode where chandler is having difficulty explaining to his boss that his "butt patting" is not appropriate. I'm not sure if this is the one your are asking about, but its a pretty funny episode.