TOW the Joke is not one of those episodes you remember long after you've seen it. Nothing much really happened, even Joey working at Central Perk seemed pretty light weight. Still it was quite funny and had some good scenes.
Ross and Chandler spend larger part of the episode arguing over who came up with a joke about a monkey doctor. Although it does get too infantile at times there are a lot of funny scenes concerning this. I especially liked the scene where they make a big deal about it to Monica and ask her to decide who made it up, and she ends up telling them that they are both idiots and that the joke sucks. Ross and Chandler continue to argue over who came up with the joke, only this time neither wants to take credit for it.
The girls talk about who they would date if they had to date one of the other two. Monica gets upset when Phoebe picks Rachel and spends larger parts of the episode obsessing over this. Phoebe's claim that Monica is high maintenence upsets her a lot, and when Chandler agrees to it she gets even more upset. Chandler however explains to her that being high maintenance doesn't have to be a bad thing and that he likes that quality in her. Phoebe suddenly finds Monica very attractive.
Joey meanwhile begins to work at Central Perk to make some money. A storyline with little comedy and little weight. We've already seen Rachel as a waitress at the coffe house, they have pretty much exhausted the storyline of a Friend working there. And they couldn't provide anything new to the Joey angle, so it all just felt pointless.
One of my favorite scenes in this episode is with Monica and Chandler in bed. Monica is obsessing over Phoebe picking Rachel and Chandler is obsessing over Ross stealing his joke. They both keep going on and on about the thing that bugs them. What I like about this scene is that even though they are both so preoccupied with their own line of thought they are still listening to each other and manage to have a conversation. It was a nice touch which shows how close they are, and that even though their own issue is driving them crazy they still care about what the other one is talking about.