Chandler mentions Michael Flatley in the episode titled "The One With the Princess Leia Fantasy," which is the third episode of season 3 of Friends. In this episode, Chandler jokes about Flatley's famous Irish dance moves during a conversation with Joey. Michael Flatley is a well-known Irish-American dancer and choreographer, best known for his work in the Irish dance shows "Riverdance" and "Lord of the Dance."
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 the Embryos
The One With All The Rugby
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 the Embryos
The One With All The Rugby
Season 2 Episode 7 The One Where Ross Finds Out
This was in season 8, episode 21, The One with the Cooking Class. Phoebe gives advice and preps Chandler for an interview.
Yes he did. It was a funny episode.
The episode is called The One with All the Thanksgivings from season 5.
Season 9, Episode 19, The One With Rachel's Dream
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.
Monica and Chandler get married at the very end of season seven.